Triaxial strength tests on till samples from the Slope Dynamics

Triaxial strength tests on till samples from the Slope Dynamics Project – Happisburgh, Sidestrand, and Aldbrough

Physical Hazards Programme

Internal Report IR/06/065

BRITISH GEOLOGICAL SURVEY

INFORMATION PRODUCTS PROGRAMME

INTERNAL REPORT IR/06/065

Triaxial strength tests on till samples from the Slope Dynamics Project – Happisburgh, Sidestrand, and Aldbrough

P.R.N. Hobbs and K. A. Freeborough

The National Grid and other Ordnance Survey data are used with the permission of the Controller of Her Majesty’s Stationery Office. Ordnance Survey licence number Licence No:100017897/2005.

Keywords

Report; coastal; landslide; till; strength; triaxial; geotechnical; Holderness; Norfolk; .

Front cover

View westward of Black Ven landslide complex.

Bibliographical reference

HOBBS, P. R. N & FREEBOROUGH, K.A... 2006. Triaxial strength tests on till samples from the Slope Dynamics Project – Happisburgh, Sidestrand, and Aldbrough. British Geological Survey Internal Report, IR/06/065. 17pp.

Copyright in materials derived from the British Geological Survey’s work is owned by the Natural Environment Research Council (NERC) and/or the authority that commissioned the work. You may not copy or adapt this publication without first obtaining permission. Contact the BGS Intellectual Property Rights Section, British Geological Survey, Keyworth, e-mail [email protected] You may quote extracts of a reasonable length without prior permission, provided a full acknowledgement is given of the source of the extract.

© NERC 2005. All rights reserved

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BRITISH GEOLOGICAL SURVEY

i

Foreword This report is the published product of part of the Slope Dynamics Project’s geotechnical investigation concerned with testing of undisturbed samples collected as part of the field programme.

Acknowledgements The authors are grateful to colleagues for assistance with sample collection; in particular to Andrew Gibson, Lee Jones, Gareth Jenkins, Catherine Poulton, and Paul Turner.

Contents

Foreword ......................................................................................................................................... i

Acknowledgements......................................................................................................................... i

Contents........................................................................................................................................... i

Summary........................................................................................................................................ ii

1 Introduction ............................................................................................................................ 3

2 Test equipment ....................................................................................................................... 3

3 Sample preparation................................................................................................................ 5

4 Triaxial test method ............................................................................................................... 6

5 Triaxial test results................................................................................................................. 7

6 Literature .............................................................................................................................. 12

7 Conclusions ........................................................................................................................... 12

Glossary........................................................................................................................................ 13

References .................................................................................................................................... 13

ii

Summary This report describes triaxial strength tests, and the results obtained, as carried out in the laboratories of the British Geological Survey on ‘undisturbed’ hand-prepared U100 samples of geological materials collected at test sites, forming part of the Slope Dynamics Project, at Happisburgh and Sidestrand (North Norfolk) and at Aldbrough (Holderness). The results are placed in the context of data available in the literature. Specimen preparation, test equipment, and test methodology are also briefly described.

3

1 Introduction As part of the Slope Dynamics Project four hand-cut undisturbed U100 samples were collected from coastal sites at Happisburgh, Sidestrand, and Aldbrough. These represent three out of twelve coastal study sites being monitored for coastal cliff recession and the contribution of landslide processes. As part of this work, a limited number of geotechnical samples were collected between 1999 and 2003. Of these, four were of ‘undisturbed’ type and intended for triaxial testing at BGS, Keyworth. The samples were taken from glacial deposits exposed in cliff sections. Two of the four samples were considered to be from within a landslide mass, and the other two were considered to be unaffected by landsliding, though adjacent to a landslide. In this context the former could be considered ‘disturbed’ though these were nevertheless collected using an ‘undisturbed’ sampling technique.

The laboratory triaxial test, as specified in BS1377:1990 and described in Head (1992), is used to measure the shear strength parameters of soils and soft rocks, namely cohesion and internal friction angle. This is achieved by subjecting a right cylindrical specimen to several stages of saturation, followed by consolidation, and finally shearing by application of an additional axial stress (‘deviator stress’). The isotropically-consolidated undrained (CIU) version of the triaxial test allows pore pressures within the test specimen to be measured throughout and hence the ‘effective’ strength parameters to be derived from the ‘total’ parameters, notwithstanding the test being carried out in an undrained state. This method allows for a more rapid test than is the case when imposing ‘drained’ conditions on such a large specimen. The multi-stage element of the test indicates that a single specimen has been used and consolidated to three effective stress stages, rather than using the more familiar three individual specimens. The reason for using the multi-stage approach is that fewer samples require less time in the field, and that issues of non-uniformity between samples is removed. The test procedure is designed to reproduce the same result as where individual samples have been used, and is generally suitable for normally and lightly over-consolidated clays (Head, 1992).

2 Test equipment The apparatus used for the triaxial tests is shown in Figure 1. This is an ‘advanced GDSTTS’ system which has a 100 mm Wykeham Farrance (Bishop & Wesley type) stress-path cell capable of testing specimens up to 100 mm in diameter and 200 mm in height. The system features automated test control and data logging via a PC. Water pressure is applied to the cell and specimen via digital controllers (pumps), which also measure volume change. Axial stress is measured via a built-in load cell. Primary and secondary pressure transducers measure ‘pore’ and ‘back’ pressures (Figure 2). The ‘back’ pressure line is connected to a digital controller in order that water can be introduced (saturation) or removed (consolidation) from the specimen. The triaxial cell differs from the standard Wykeham Farrance design in having two de-airing junction blocks serving both top and bottom specimen ports, rather than just one. The axial ram is hydraulic and operates via a Bellophram™ double rolling seal and Rotolin™ linear bearing housed in the lower half of the cell. This mechanism serves to isolate the pressured cell fluid from the ram.

4

Figure 1 GDS advanced triaxial system with 100 mm Bishop & Wesley cell (right) and digital controllers (centre)

Figure 2 Schematic of GDS 100 mm triaxial system

Load cell

Ram

5

3 Sample preparation Samples were received from the field in sealed 103 x 250 mm plastic tubes and stored in a special temperature and humidity controlled room. To prepare a triaxial specimen, the sample was removed from its plastic sleeve and trimmed to a length of about 200 mm. The diameter was not trimmed to 100 mm diameter as it was felt that this would induce excessive disturbance. However, any large voids were filled with a paste made up from cuttings from the sample (Figure 3). This specimen ‘repair’ was used so that the rubber membrane subsequently applied to the specimen would not fail as a result of penetrating voids in the specimen. Such a procedure does not significantly affect the bulk properties or strength. Following this, a moist vertical filter drain was applied to the surface of the specimen, filter papers and saturated filter discs applied to top and bottom, and a 100 mm rubber membrane jacket applied.

Figure 3 Trimming and ‘repair’ of triaxial specimen Filter paper drains were used to speed up consolidation. These do not significantly affect the strength parameters of stiff clays. The sample details are shown in Table 1. It was not possible to assign a formation to the two Sidestrand samples as they were taken from within landslide masses.

6

Location Position,

depth

Samp. No.

Date

collected

Formation Member Lithology

Happisburgh Lower cliff 0.25m

HB4

19/04/01 Happisburgh Formation

Happisburgh Till Member

Dark-grey sub-glacial till

Sidestrand Mudslide, 0.15m

ST4 20/04/01 unknown unknown Medium grey silty clay till

Sidestrand Debris flow 0.15m

ST5 20/04/01 unknown unknown Light grey till

Aldbrough below cliff crest, 3.8 m

ALD1 19/08/04 Holderness Formation

Withernsea Member

Grey till

Table 1 Samples for triaxial testing

4 Triaxial test method Following mounting of the test specimen in the triaxial cell, and filling of the cell with de-ionised / distilled water, a small effective stress was applied (5 kPa) in order to check that a leak-free system had been established. The sample was then subjected to several cycles of saturation via the back-pressure line followed by B-checks, maintaining an effective stress of 5 kPa throughout in order to keep the membrane in contact with the specimen. The total stress was ramped up to 300 kPa during this process in order to increase the degree of saturation. The process was considered complete once the B-value had reached 0.95. At this point the first stage of isotropic consolidation was applied over 24 hours at an effective stress of 50 kPa (Cell pressure= 350 kPa, back pressure = 300 kPa), followed by axial undrained compression loading at a rate of +0.2 mm/min, and unloading at –0.2 mm/min. As this was a multi-stage test the specimen was not compressed to the point of failure, but the loading terminated when a peak stress ratio was reached, followed immediately by unloading to the pre-compression axial force. This enabled the axial stress to be returned to its post-consolidation isotropic value. The stage 2 consolidation at an effective stress of 100 kPa was then run over a 24 hour period, followed by stage 2 loading and unloading. Finally, stage 3 consolidation and stage 3 loading/unloading at 200 kPa effective stress were applied. The stage 3 loading was taken to axial strains beyond the point where shear failure was considered to have occurred.

Stage 1 2 3 Saturation (back pressure)

0 – 300kPa CP in 3 - 5 stages,

(5 kPa effective)

-- --

Isotropic consolidation (drained one end)

50 kPa effective, drainage to 300 kPa BP



Axial compression (undrained loading)

Undrained, with PP 0.2 mm/min



Axial extension (undrained unloading)

Undrained, with PP -0.2 mm/min

Undrained, with PP - 0.2 mm/min

Undrained, with PP -0.2 mm/min

Table 2 CIU multi-stage triaxial test method

7

5 Triaxial test results The results of the triaxial tests are summarised in Table 3 and in plots in the Appendix. The abbreviations used are explained in the Glossary. Figures 6a to 6d show the stress-path plots derived from the triaxial tests. Both the ‘total’ and ‘effective’ stress-paths are shown, the difference between them (x-axis) being the pore pressure increase, Δu, measured during the compression stage of the test (that is u0 reduced to zero in each case). In each case the stress-path direction is upward (i.e. increasing stress). The stress-paths for the decompression (axial unloading) stages are not shown. Table 4 shows the MIT parameters s’ and t’ (Head, 1992) used to define the failure envelope and hence the strength parameters c’ and φ’.

Sample w0

(%) γd0

(Mg/m3)

mvi

(m2/MN)

c’

(kPa) φ'

(degr.)

Shear rate

(%/min)

HB4 14.0 1.94 0.4 – 0.5 28.8 24.4 0.1

ST4 22.0 2.06 - 0.4 26.7 0.1

ST5 21.7 1.52 0.7 – 1.5 7.4 17.6 0.1

ALD1 13.0 1.88 0.7 – 1.0 3.8 26.4 0.1 Table 3 Triaxial test results

Stage 1 Stage 2 Stage 3

Sample s' t' s' t' s' t' (kPa) (kPa) (kPa) (kPa) (kPa) (kPa)

HB4 56.32 45.82 129.93 84.73 256.98 140.98

ST4 43.4 19.5 65.36 30.16 119.3 53.8

ST5 34.95 17.45 85.44 33.04 202.91 68.21

ALD1 38.77 18.87 92.56 47.16 209.59 95.89

Table 4 Details of effective stress-path parameters at failure (Mean effective stress, s’, maximum effective shear stress, t’)

8

Figure 4 Happisburgh HB4 triaxial test specimen (post-test)

Figure 5 Aldbrough ALD1 triaxial test specimen (post-test)

Post-test photos of the Happisburgh and Aldbrough samples are shown in Figures 4 and 5. No photos are available for the Sidestrand specimens.

9

Triaxial test - stress-path plot [HB4]

0

20

40

60

80

100

120

140

160

0 100 200 300 400

Normal stress - total & effective (kPa)

Shea

r str

ess

(kPa

) Stage3 - tot

Stage3 - eff

Stage2 - tot

Stage2 - eff

Stage1 - tot

Stage1 - eff

Figure 6a Stress-path plots for total and effective compression states – sample Happisburgh, HB4

Triaxial test - stress-path plot [ST4]

0

20

40

60

80

100

120

140

160

0 100 200 300 400


Shea

r str

ess

(kPa

) Stage3 - tot

Stage3 - eff

Stage2 - tot

Stage2 - eff

Stage1 - tot

Stage1 - eff

Figure 6b Stress-path plots for total and effective compression states – sample Sidestrand, ST4

10

Triaxial test - stress-path plot [ST5]

0

20

40

60

80

100

120

140

160

0 100 200 300 400


Shea

r str

ess

(kPa

) Stage3 - tot

Stage3 - eff

Stage2 - tot

Stage2 - eff

Stage1 - tot

Stage1 - eff

Figure 6c Stress-path plots for total and effective compression states – sample Sidestrand, ST5

Triaxial test - stress-path plot [ALD1]

0

20

40

60

80

100

120

140

160

0 100 200 300 400


Shea

r str

ess

(kPa

) Stage3 - tot

Stage3 - eff

Stage2 - tot

Stage2 - eff

Stage1 - tot

Stage1 - eff

Figure 6d Stress-path plots for total and effective compression states – sample Aldbrough, ALD1

11

Stress failure plot

0

20

40

60

80

100

120

140

160

0 50 100 150 200 250 300

Mean effective stress, s' (kPa)

Max

imum

effe

ctiv

e sh

ear s

tres

s, t'

(kPa

)

HB4ST4ST5ALD1

Figure 7 Plot of stresses at compression failure (s’ vs. t’) for all samples

The stress-path plots show a range of behaviour from over-consolidated to lightly over-consolidated (normal consolidation is indicated by continued divergence of a pair of ‘effective’ and ‘total’ curves whilst over-consolidation is indicated by convergence prior to failure). Specimens ST4 and ST5 show normal consolidation due to remoulding as part of mass movements, and the associated destruction of their former (presumed) over-consolidated fabric. Specimens HB4 and ALD1 appear to be lightly over-consolidated at the stresses applied. None of the specimens appear to show a distinct transition from one state to another at the stresses applied. With respect to the isotropic consolidation stages of the tests, considerable reduction in volume change was found from stage 1 to stage 2, whereas Stages 2 and 3 were similar in terms of volume change. The values for the isotropic coefficient of volume compressibility, mvi, (Table 2) fall in the ‘medium’ to ‘high’ range. Head (1986) gives the following theoretical relationship between isotropic and one-dimensional coefficients:

mvi = 1.5mv

The above relationship assumes isotropic behaviour, which is probably incorrect for a till. However, the values thus obtained (Table 2) appear to be reasonable particularly when considering that two of the tills are disturbed.

12

6 Literature Few geotechnical data are available in the literature for the tills of north Norfolk. However, Bell (1991) reported that they tend to be matrix dominant with ‘firm’ to ‘stiff’ consistency, ‘low’ to ‘intermediate’ plasticity, and with an undrained shear strength of between 50 and 115 KPa. The tills have low strength sensitivity and are ‘inactive’ to ‘normally active’. Bell (1991) also reported that strength is particularly sensitive to water content. The Cromer Till consists of an upper and lower member in parts separated by laminated silts and clays. The Happisburgh Till Member, represented by sample HB4, unconformably overlies the marine deposits of the How Hill Member (Wroxham Crag Formation) and is the basal member of the Happisburgh Formation (Lee et al., 2004). This unit consists of an over-consolidated grey, massive, matrix-supported ‘diamicton’ that contains occasional sheared inclusions of crushed chalk and Crag material. It was deposited as subglacial deformation till that accreted by processes of subglacial lodgement and pervasive sub-horizontal shearing. The deposits in the mid part of the cliff at Sidestrand, which are probably the source materials for samples ST4 and ST5, consist of the Ostend Clay Member (Happisburgh Formation), the Walcot Till Member (Lowestoft Formation), Bacton Green Till Member (Sheringham Cliffs Formation) (Lee et al., 2004). These consist mainly of uniform fine-grained silts with clay and a relatively minor clast content, a proportion of which is chalk.

A large study of till was made at Cowden on the Holderness coast (2 km north of Aldbrough). This site was set up in 1976 by the Building Research Establishment (BRE) to study a typical lowland, matrix dominant, till and to relate this to tills found in the North Sea as a result of oil and gas field development. The testing programme included a wide variety of in-situ and laboratory investigations (Marsland & Powell, 1985). The two major Late Devensian Till formations on the Holderness coast are the Withernsea Member (formerly ‘Withernsea Till’) and the underlying Skipsea Member (formerly ‘Skipsea Till’), both part of the Holderness Formation; sample ALD1 representing the former. These are believed to be lodgement tills (Lewis, 1999). These tills are matrix dominant and have a clay mineralogy of kaolinite and illite (kaolinite increasing upward), and a clay size content of up to 40 % (Bell & Forster, 1991). The plasticity classification of the tills is ‘low’ to ‘intermediate’; the Withernsea Member being somewhat more plastic than the Skipsea Member. All tills plot well above the Casagrande A-line. There is an overall, but slight, coarsening upward of the clay / silt particle size from the Basement Till to the Skipsea Member. Strength tends to decrease upward; the Skipsea Member being stronger than the Withernsea and the highly weathered near-surface material. Low strength sensitivity to remoulding was noted throughout, as was the case for the Norfolk tills. Bell & Forster (1991) quote values for c’ and φ’ of 42 kPa and 26 o respectively for the Withernsea Till.

7 Conclusions The triaxial data cover a range of tills, two of which (ST4 & ST5) were from landslide masses. The strength results for the latter therefore strictly refer to ‘remoulded’ strength. This is confirmed by the stress-path trends, and indicates that these tills are behaving as normally-consolidated, having lost any over-consolidated characteristics. However, effective strength does not appear to have been greatly affected, although any strength reduction cannot be assessed as no ‘unslipped’ specimens were available for test. Lodgement tills might be expected to have a high density and strength compared with their remoulded equivalent. Whilst a direct comparison cannot be made here, the results show that the light grey till (sample ST5) from the debris flow

13

at Sidestrand has a significantly lower effective strength, in terms of friction angle, and a lower dry density than the others.

Glossary BP Back pressure (applied pressure within specimen) CP Cell pressure (applied pressure to water-jacket surrounding specimen) c’ Effective cohesion φ' Effective friction angle eff. Effective mv Coefficient of volume compressibility (one-dimensional) mvi Coefficient of volume compressibility (isotropic) PP Pore pressure (measured pressure within specimen) s’ Mean effective stress (MIT terminology) t’ Maximum effective shear stress (MIT terminology) tot. Total w0 Initial water content γd0 Initial dry density

References Bell, F.G. (1991) A survey of the geotechnical properties of some till deposits on the north coast of Norfolk. In: Quaternary Engineering Geology. Geological Society, Engineering Geology Special Publications, No. 7. Forster, A., Culshaw, M.G., Cripps, J.C. Little, J.A. & Moon, C.F. (eds.). pp 103-110. London.

Bell, F.G. and Forster, A. (1991) The geotechnical characteristics of the Till deposits of Holderness. In: Quaternary Engineering Geology. Geological Society, Engineering Geology Special Publications, No. 7. Forster, A., Culshaw, M.G., Cripps, J.C. Little, J.A. & Moon, C.F. (eds.). pp 111-118. London.

BS1377:1990 (1990) Method of test for soils for civil engineering purposes. British Standards Institution, London.

Head, K.H. (1992) Manual of soil laboratory testing. Vol. 3, effective stress tests Wiley

Lee, J.R., Booth, S.J., Hamblin, R.J.O., Jarrow, A.M., Kessler, H., Moorlock, B.S.P., Morigi, A.N. Palmer, A., Pawley, S.J., Riding, J.B., and Rose, J. (2004) A new stratigraphy for the glacial deposits around Lowestoft, Great Yarmouth, North Walsham, and Cromer, East Anglia, UK. Bulletin of the Geological Society of Norfolk, 53, pp3-60.

Lewis, S.G. (1999) Eastern England. In: A revised correlation of Quaternary deposits in the British Isles. D.Q. Bowen (ed.) Geological Society Special Report No. 23.

Marsland, A. & Powell, J.J.M. (1985) Field and laboratory investigations of the clay tills at the Building Research Establishment test site at Cowden, Holderness. Proc. Int. Conf. on Construction in Glacial Tills and Boulder Clay, Edinburgh, pp147-168.

This page is blank

APPENDIX

Triaxial test data sheets(produced automatically by GDSTTS software)

, .

British Geological Survey

Consolidated Undrained Triaxial Compression TestBS 1377: Part 8 : 1990

Stage 3Stage 2Stage 1

Job Ref.Job Location HappisburqhBoreholeSample No. HB4 HB4 HB4Depth m 0.25 0.25 0.25Dale 19/04/01 19/04/01 19/04/01Disturbed 1Undisturbed undis undis undis

~ 0; Specimen Details'" 'iiio 0

:>. >-0 .0

-g ~ Description of Specimen"'" ,:;~ ~ Lower Till [Happisburgh Formation, Happisburgh Till Member]

Initial Specimen Conditions

Load rate = 0.2 mmlmin

~0Q..,II:v;~

,;I

?:Vl'5.0if>Cia.'";;;!'l

'"u----'«x<lii

~.i(

-~;;;a~II:

8<l ,...II: 0

g 0~

<l '"~ ~Iii N

ojC'" "c.!!! 'iiiu::: a

Height mm 200.00 196.06 192.48Diameter mm 103.00 103.09 103.62

Area mm2 8332.29 8346.09 8433.68

Volume cm 31666.46 1636.31 1623.27

Mass Ir- 3753.00-

9 -Dry Mass g 3227.28Density Mg/m3

2.25Dry DenSity Mg/m3 1.94Moisture Conlenl % 14.00 14.00 14.00Degree of Saluration %Specific Gravity kN/m3

(assumed/measured)

Final Specimen ConditionsMoisture Conlenl % 12.61Density Mglm3

2.28Dry Densl1y Mg/m:l 1.94

Sketch of Failure of the Specimen


Consolidated Undrained Triaxial Compression TestBS 1377 : Part 8 1990

Specimen DetailsStage 1 Stage 2 Stage 3

Job ReI. 0Job Location HaDptsburQhBorehole 0 0 0sample No. HB4 HB4 HB4Depth m 0.25 0.25 0.25Date 19/04/01 19/04101 19/04/01

Consolidation

SaturationCell Pressure Incr. kPa 18.70 20.30 19.90Back Pressure Incr. kPa 18.10 17.20 17.90DiHerenlia! Pressure kPa 290 7.60 7.20Final Cell Pressure kPa 23.70 118.90 219.00Final Pore Pressure kPa 31.00 117.90 218.50Final B Value 0.93 0.84 0.88

Effective Pressure kPa 1.20 31.80 80.20Cell Pressu re kPa 399.20 395.30 448.60Back Pressure kPa 398.00 363.50 368.40Excess Pore Pressure kPa 357.60 345.50 360.70Pore Pressure at End kPa 6.30 7.00 6.70

Consolidated Volume em3 1636.31 1623.27 1610.54Vo\umelric Strain 0.006030756 0.002654961 0.002615905Consolidated Heighl mm 198.79 195.54 191.97

Consolidated Area mm2 8231.79 8301.77 8389.55

Vol. Compressibility m2fMN 0.38741 0.31860 0.54498

Consolidation Coel. m~/yr.

Dale started 27/06/05 27106/05 27/06/05Date FinishedTop Drain Used y y yBase Drain Used y y ySide Drains Used y y yPressure System NumberCell Number

(;"-'"cr:~:<

~

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2


Consolidated Undrained Triaxial Compression TestBS 1377 : Part 8 : 1990

Stage 1 Stage 2 Stage 3S DIspecimen etal S

Job Ref. DJob Location HaoDlsburahBorehole 0 0 0sample No. HB4 HB4 HB4Depth m 0.25 0.25 0.25Date 19/04/01 19/04/01 19/04/01

Consolidation Stage

~Stage 1 I

_Stage 2

-.-Stage3 '

4035

j

.

30

1000

----+----~L

Square-rool TIme (min)

15 20 25

-'+-Slage I

10000 _Stage 21---#'--------------l---------l "",,-S[8ge 3 I

105

6----+-----+------------

30

5-l+-....~,.--j----1-----:---------------------l

1O+-I------:l...~..-=--+-----------------------___i

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1000

800

600/ ...,'"

l 400c,2

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·1000

·1200

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Time (min) on logarithmic sca~

3




Job Ref. 0Job Location HappisburqhBorehole 0 0 0Sample No. HB4 HB4 HB4Depth m 0.25 0.25 0.25Date 19/04/01 19/04/01 19/04/01

Initial Cell Pressure kPa 401.5 449.1 547.5Inillal Pore Pressure kPa 366 349.4 361.4Rate of Strain %/hour 5.99994 6.120612501 6.234503027

Max Deviator StressAxial Strain 1.337 1.533 3.121Axial Stress kPa 102.12 193.45 291.92Cor. Deviator stress kPa 102.12 193.45 291.92Effective Major Stress kPa 120.62 251.85 441.12Effective Minor Stress kPa 18.50 58.40 14920Effective Stress Ratio 6.520 4.313 2.957s' kPa 69.56 155.13 295.16l' kPa 51.06 96.73 145.96Shear Resistance Angle degs 24.45 24.45 24.45Cohesion c' kPa 28.78 28.78 28.78

Max EHectilie Principle Stress RatioAxial Strain 1.004 0.853 1.559Axial Stress kPa 91.64 169.47 281.96Cor. DeViator slress kPa 91.64 169.47 281.96Effective Major Stress kPa 102.14 214.67 397.96Effective Minor Stress kPa 10.50 4520 116.00Effective Stress RatiO 9.728 4.749 3.431$' kPa 56.32 129.93 256.98I' kPa 45,82 84.73 140.98

8-IDa:v;)(

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4



Stage 3Stage 2Stage 1Specimen DetailsJob Ref. 0Job Location HappisburqhBorehole 0 0 0Sample No. HB4 HB4 HB4Depth m 0.25 0.25 0.25Date 19/04/01 19/04/01 19/04/01

Shearing Stage

Slope Dynamics Project - Happisburgh. HB4Multi-stage CIU Triaxialtesl

-- -,-- -

~-=_. -- I- -.--c- -

~ -- ---I I

I

I

I

I

- .~ r---

-+-Stage 1

--'-Stage2

......-Stage3

-+-Stage 1 I__._Sfage2

.....-S~age~1

4,5

4,5

4

4

3.5

3,5

3

3

2,5

2.52

2.

Axial Strain (%)

----' -----I

--- - ------+------------1

t,50.5

350

300

~ 250~

'"~ 200(Jj

0 1SO7ii'~

1000

50

05

soo

450

150

3SO

400

100

50

oo

Iii'0-~ 300e:J~ 250f0-.. 200(;ll.

t::0o.

'"II:~

"Qli::r:::>'i=-!?::>

.D<Jl

Ci-0.raJ:"iiim..,~

«~iI~

'"'xcaEIj)c.JCls:II:0I-« r--a: 0

:il 0

« ~;:J QW w

""

0;E'" ;,;c:

'" 0;~ c.J

Axial Strain (%)

5



Sample DetailsStage 1 Stage 2 Stage 3

Job Ref 0Job Localion HappisburghBorehole 0 0 0sample No. HB4 HB4 HB4Depth m 0.25 0.25 0.25Date 19/04/01 19/04/01 19/04101

--Stage 1

--Stage 2

--Stage 3

li

r-+-Sla99 1 ..-.- Stage 2 I1---.- S~age 3 !

4.5

500450

4

'--r--

'!DO

3.5

350

3

300

25

250

2

Axial Slre,n (%)

200

t.5

Slope Dynamics Project - Happisburgh, HB4Multi-stage CIU Triaxial test

15010050

0.5

250 .,----,---..,....---.----,------..,---..,-----r------;-----,

50 -I----:=?-+--=----.J+--+---~------+-----_T_..,--___1

}~ 150 +---+----'---+---~e~ 100 +----t---,------=::::i~S:::::::r_r_-- ~OJQ)~(/)

Shearing Stage

12 -,10

.e..a:III

fiii! 6Zi.5Ii:

~u..~Ul

2

t:'0Q.

'"a:"ffi~

C1iJ:~e''"D<f>Q.

:?:;s'"'"--'«~rr:I-

""'"'X~~(/)a~a:0I-« !'-a:: 0

~0

« ~~

0i<lw '"

<IiE~ 2~ '"u: 0

Nonnal Effective Stress (kNJm~)

6




Job Ref. 0Job Location HappisburghBorehole 0 0 0Sample No. HB4 HB4 HB4Depth m 0.25 0.25 0.25Date 19/04/01 19/04/01 19/04101

Shearing Stage

Slope Dynamics Project - Happisburgh, HB4Mulli-slage CIU Tnaxiallest

I I

I II

-.I

f- -- -- i- - --- - --.

(-----

.~-_._- - -

( I ) I

Normal Effective Stress (kNlm2)

e00-Q)

ll:Vi><'<t!XlJ:,.s:::0>:;.0<J>a.0.

'":t:~a;TI-.J~

X~a::!2'"'x'"g,Cl

~0:0I-« l:3a:~

0

;;5 ~W N

<DE

'" 0;c~ <iii.i: Cl

250

Ne 200z~

~ ISOiii

ith 100

.~(;~ 50W

aa 50 100 150 zoo 2SO 300 350 400

I-stage 11

I _'I-S!age3

450

7



Job Ref. Slope DynamicsJob Location Sidestrand mudslideBoreholeSample No. 5T4 8T4 8T4Depth m 0.15 0.15 0.15Date 20/04/01 20/04101 20/04/01Disturbed 1Undisturbed Undist. Undis\. Undist.

., Oi Specimen Details~ OJo 0


t:"c.Ol([OJ"x-iI-eI)

;gc'"~tI>

'""0Uj"§co

"0->«X«0:I-

""co;<,~

U50

~([

0I-« "-CI: 00 0m ~«-' ~.;---:lU N

(I)

EO'" .,c~ '"u: 0

Description of Specimen

I mld-greyTILL [mudslidel

----------

Initial Specimen ConditionsHeight mm 211.00 203.90 198.68Dlameler mm 103.00 102.44 103.68

Area mm2 8332,29 8241.45 8442.20Volume cm3 1758.11 1680.41 1677.29Mass 9 3695.60 3695.60 3695.60Dry Mass 9 3018.16

Densrly Mg/m3 2.10 2.20 2.20

Dry DenSity Mg/m32.06

Moisture Content % 21.99 21.99 21.99Degree of Saturation %Specific Gravity kN/m3

(assumed/measured)

Final Specimen ConditionsMoisture Conlent % 18.33

DenSity Mg/m32.20

Dry Density Mg/m31.93


_.

~Stage 1 Stage 2 Slage 3




Job ReI. Slope DynamicsJob Location Sidestrand mudslideBorehole 0 0 0Sample No. ST4 ST4 5T4Depth m 0.15 0.15 0.15Date 20/04/01 20/04101 20/04/01

Dale started 14/06/05 14/06/05 14/06/05Date FinishedTop Drain Used y y yBase Drain Used y y ySide Drains Used y y yPressure System NumberCell Number

£ 1; Test Setup"'" -04> ~

~ ~>: CoU <t

<;0-

'"II:~

><~

'"~c'"iii'"-0en'§'"-0-'«X«cr~

'"~iii0CJ>=([

0f-« .....([ c0 cm ~« ..,::! 0

<?;Li.j ('\J

'"E'"c .,!fl ;:;i.i: a

SaturationCell Pressure Incr. kPa 19.10 18.70 18.70BaCk Pressure Incr. kPa 17.10 19.00 19.00Differential Pressure kPa 8.40 0.40 0.40Final Cell Pressure kPa 219.40 319.00 319.00Final Pore Pressure kPa 214.50 322.50 322.50Final B Value 0.91 1.01 1.01

Consol idationEffective Pressure kPa 0.40 54.70 89.90Cell Pressure kPa 318.10 401.00 449.00Back Pressure kPa 317.70 346.30 359.10Excess Pore Pressure kPa 321.90 368.70 398.80Pore Pressure at End kPa 4.20 22.40 39.70

Consolidaled Volume cm3 1680.41 167729 1674.04Volumelric Strain 0.014732273 0.0006185 0.000646677Consolidated Height mm 207.89 203.77 198.55


Vol. Compressibility m2IMNConsolidation Ceel. m2/yr.

2




Job Ref. Slope DynamicsJob Location Sideslrand mudslideBorehole 0 0 0Sample No. ST4 ST4 514Depth m 0.15 0.15 0.15Date 20/04/01 20/04/01 20/04/01

Consolidation Stage

Slope DynamiCS Project - Sidestrand. ST4Multi-slage CIU Triaxiallesi

SQuare-rOOI Time (min)

I I

1--

I :2 3 6I

.~- - -

-.---- -,I

11_ T ....... -

-- -. i - - - 0'

J

-.-Stage 1

_518ge21--,-Slage 3 :

-'-Stage 1

_Slage21-+-Slage3

o!'" ,to 190 l~O wilo

I I

'/ I

I

VII

I

,

-40

-20

"E0

~ 20lD...<:.. 40.<:u..E 60::I

Ci> 80

100

120

a

-:2500

-500

·2000

~c.~

~ -\000'in/I}

ClD

OJ~ -1500l!?"lD

(;"-

to0Cl.Q)

a:Ui

"""I-<I)

;gcOJ

~

'""t)

0OJ;;;"0-'«

~a:I-..::

'"i<OJ

"SIf)0

~:J:0I-< ~a: 00 0aJ C!;1

(J;)

~W N

;,;E<II

Qic:~ ;:;;i:L 0

Time (min) on logarithmic scale

3




~Q.

'"a:Vi)(qt-

~-cc:~iii

'"'0iii'il:a;-c~

~

~~I-

~)<

.~

iJi0

'">=cc0....~ r-..a: 00 0rn N

-< <:a....J a.,.. illw <'\l

'"Eto

~c:~ IIIIT: 0

Job Ref. Slope DynamicsJob Location Sidestrand mudslideBorehole 0 0 0sample No. ST4 ST4 ST4Deplh m 0.15 0.15 0.15Date 20/04/01 20/04/01 20104/01

eanngInitial Cell Pressure kPa 400.3 450.4 549.9Initial Pore Pressure kPa 345.5 364.4 385Rate of Strain %/hour 5.687146919 5.885251443 6.039821548

Max Deviator StressAxial Strain 1.759 2.450 3.688Axial Stress kPa 39.00 60.32 107.61Cor. Deviator stress kPa 39.00 60.32 107.61Effective Major Stress kPa 62.90 95.52 173.11Effective Minor Stress kPa 23.90 35.20 65.50Effective Stress Ratio 2.632 2.714 2.643s' kPa 43.40 65.36 119.30t' kPa 19.50 30.16 53.80Shear Resistance Angle degs 26.70 26.70 26,70CoheSion c' kPa 0.36 0.36 0.36

Max Effective Principle Stress RatioAxial Strain 1.759 2.450 3.688Axial Stress kPa 39.00 60.32 107.61Cor. Deviator stress kPa 39.00 60.32 107.61Effective Major Siress kPa 62.90 95.52 173.11Effective Minor Stress kPa 23.90 35.20 65.50Effective Stress Ratio 2.632 2.714 2.643s' kPa 43.40 65.36 119.30l' kPa 19.50 3016 53.80

4



Stage 1 Stage 2 Stage 3Specimen DetailsJob ReI. Slope DynamicsJob Location Sideslrand mudslideBorehole 0 0 0Sample No. 5T4 ST4 ST4Depth m 0.15 0.15 0.15Date 20/04/01 20/04/01 20/04/01

Shearing Stage

-+-Slage 1

....... Sla.ge2

---.-Stage 3..

-+-Stage I__Slage2'

---.-Stage 3 I

4.5

4,5

4

4

3.5

35

3

32.5

252

2

Axial Stra.in (%)

1.5

1.5

Slope Dynamics Project· 5ideslrand, 5T4Multi-slage CIU Triaxial lest

Slope Dynamics Project - Sideslrand. ST4Mulh-stage CIU TrialCiallesl

0.5

II

------'T' r --..-~~ -~ I

,

,.-t--- - - - I

1I

I

I II I

I

120

100

ii0..

80~

'"'"..~ 60

0<ii'; 40.,c

20

0.5

500

600

100

oo

~400~

e:::J

::: 300..0:..o 2000..

t::0"-illCI:-;;;><..".r-w;;;c~"iii(J)"0

~'""t)..J«~a:1-

"'"II>:~C1>0

~a:0....« t-o: 0

~0~

« '£i

? 0;0

Li.J '"

.,;EOJ

OJc!!! '"u: 0

Axial Strain (%)

5




'" '"ru 'iiio 0

Job Ref. Slope DynamiCSJob Locahon Sidestrand mudslideBorehole 0 0 0Sample No. 5T4 514 5T4Depth m 0.15 0.15 0.15Dale 20/04/01 20/04101 20/04/01

Shearing Stage

Slope Dynamics Project - Sidestrand. S14Mulli-stage CIU Triaxialtesl

--Stage 1

--Stage 2--Stage 3

-.-Stage'__Stage 2

-...-Stag~

4.5

200180

4

160

3S

\40

3

120

2.5

100

2

80

15

6040

0.5

20

I I

. - -- -.- - .-

~-~

~I ...........-: -l

I~ I ~ I

~/ "" _.-

~ ;-"" , l -\ -

~I ~ I \~ ( ( !\ I \ \

Altial Strain (0/0)

Slope Dynamics Project - Sidestrand. ST4Multi-stage CIU Triaxial test

oo

O+-----,----t----""T"""---+----I----+-----+---~--

o

3 ..-----,---.,.----------,----------r----;----

.~u'"ffi 05 -1-------1-----

100

90

80;:0- 70EZ

60~.,~ 50iii

40iii..ti 30

20

10

t:0a...a:7ii;:;..I-(Jl

~c.M

~.."0

~'"'0.-J«X«ii:l-e:;rtl.~

'",<f)0

~cr:0I-« .....a: 00

~(!}

~ ~

'"'<DN

aiE

'" ojc:.. ;;;li: 0

Normal EHec1i\l& SIress (kNhn')

6



Stage 1 Stage 2 Stage 3Sample DetailsJob Ref. Slope DynamicsJob Location Sidestrand mudslideBorehole 0 0 0Sample No. ST4 ST4 ST4Depth m 0.15 0.15 0.15Date 20/04/01 20/04101 20/04/01

Shearing Stage

,--------

Slope Dynamics Project - SidestranCl, ST4Multi-stage GIU Tnaxiallest

II1-'-.

I ,

--. ~

iI- I

-- r---- ---- I - ,

I I ft+-- i~

I

--~ ~f- I

~

'"r-... I

1---' ---'~-r- \..- - f-~ -

i II I


t:0Cl.III

IT:0;)(

'"....(/)

~c;

'"""'"CD~

~;;"0--'~

~n:~"")(ttl'5(/)

0

"s:a:0I-« 1'-a: 00 0al ~~ ~w C\l

Q;E'" ;,,;<:~ 'i<iu: 0

100

90NE 80Z::! 70...II>

60eiii

50iii41.r. 40

1IIIII

30,~

U41 20:t:w

10

oo 20 40 60 80 100 120 140 160 \80

--Stago 1

-Stage 2

--Stage 3

200

7

------------------------- -



Job Ref. Slope DynamicsJob Localion SidestrandBoreholeSample No. ST5 STS STSDepth m 0.15 0.15 0.15Date 20/0412001 20/04/2001 20/04/2001Disturbed / Undisturbed undisturbed tube undisturbed tube undislurbed lube

a; ., Specimen Details(ti coo 0


~0Q.Ola:Ii)><vif0-Ul

~c<II.":E'0

~;;;-0--'«X«rrfo-.::'""':!1iii0~

>:a:0fo-« t"-o: 00 0a:l ~<{

:::J0i3w N

;;E<II

ji Q)

;0i.i: 0

Description of Specimen

I light grey lil! (debris flow)

--------------'

Initial Specimen ConditionsHeight mm 197.00 190,14 183.74Diameter mm 103.00 103.21 103.77

Area mm2 8332.29 8366.41 8457.72Volume cm~ 1641.46 1590.80 1553.98Mass g 3291.00 3291.00 3291.00Dry Mass g 2500.27

DenSity Mg/m3 2,00 2.07 2.12

Dry Density Mg/m3 1.52MOisture Conlent % 24.03Degree 01 Saturation %Specific Gravity kN/m~

(assumed/measured)

Final Specimen ConditionsMoisture Conlen! 0/0 20.14

Density Mg/m3

Dry Density Mg/m31.72


--

{--- --- -

Specimen 1 Specimen 2 Specimen 3


Consolidated Undrained Triaxial Compression Test88 1377: Part 8 : 1990


Job ReI. Slope DynamicsJob Location SidestrandBorehole 0 0 0Sample No. STS ST5 ST5Deplh m 0,15 0.15 0.15Date 20/04/2001 20/04/2001 20/04/2001

Dale started 20/06/05 20/06/05 20/06/05Date FinishedTop Drain Used y y yBase Drain Used y y ySide Drains Used y y yPressure System NumberCell Number

>- >- Test SetupI:J .£)

'0 '0., !!~ [.J;; a.u '"

<50.

"'a:<;;:;;:cOf0-Ul~c'"~U>(I)

'0

~(G'0-'

'"X«a:I-f,j)(OJ

~Cl<.'J5=a:0I-

'" ....a: 0

g 0(\J

;5 i30«;

Lu (\J

iDEOJ

inc~ (iiG:- o

Saturation

Cell Pressure Incr. kPa 17.60 17.60 17.60Back Pressure InCL kPa 17.60 17.60 17.60Differential Pressure kPa 0.10 0.10 0.10Final Cell Pressure kPa 18.70 18.70 18.70Final Pore Pressure kPa 21.00 21.00 21.00Final 8 Value 1.01 1.01 1.01

ConsolidationEffective Pressure kPa 0.10 28.50 58.10Cell Pressure kPa 19.00 56.60 105.90Back Pressure kPa 18.90 28.10 47.80Excess Pore Pressure kPa 21.50 25.00 22.00Pore Pressure at End kPa 2.60 12.90 12.70Consolidated Volume cm3 1590.80 1553.98 1512.81Volumetric Srrain 0.01028799 0.007714153 0.008832567Consolidated Height mm 194.97 188.67 182.11Consolidated Area mm2 8160.84 8237.33 8308.32Vol. CompressIbIlIty m2/MN 1.44640 0.68825Consolidation Coel. m~/yr.

2



Stage 1 Stage 2 Stage 3Specimen DetailsJob Ref. Slope DynamicsJob Location SideSlrandBorehole 0 0 0Sample No. ST5 S15 ST5Depth m 0.15 0.15 0.15Dale 20104/2001 20/04/2001 20/04/2001

'" lD~ crJo 0

Consolidation Stage

'>. >.L:J L:J

'" '" Square-root Time (min)II>Q)

'":<: 00

& \0 20 30 40 50 60 70~cu «

10

L

~0

200-

'"a: ~Vi' ..>< '" -+-Stage I<Ii c:

_S1age21.. 30I- J::.rfJ U;g

'"---.- Stage 3 I

c E~ :IVi "0 40II> >'"0'"n;

50l;;J --r...J« I~a: 60I-

""'"'"~US0

~ 400 .a:0

200I-« t-IT: 00 0co '-" 0

~U>e

~ 0'<DUJ N ·200c:

0:>.. ·4000-

m 'iii I-+-Stage IE al

<"3 (5 ·600c: CD I-Stage 2$ Oi ~:.i: 0 ::J i-'-~~.al

al -800!a.! ·100000-

·1200

-1400

-1600


J

3




Job Ref. Slope DynamicsJob Location SidestrandBorehole 0 0 0Sample No. STS ST5 ST5Depth m 0.15 0.15 0.15Dale 20/04/2001 20/04/2001 20/04/2001

Inilial Cell Pressure kPa 59.5 1095 209.7InitIal Pore Pressure kPa 22.6 22 20.5Rate of Strain %/hour 6.091309645 6.311034028 6.53106277

Max Deviator StressAxial Strain 2.478 2.618 2.711Axial Stress kPa 34.89 66.09 136.42Cor. Deviator stress kPa 34.89 66.09 136.42Effective Major Stress kPa 52.39 118.49 271.12Effective Minor Siress kPa 17.50 52.40 134.10Effective Stress Ralio 2.994 2.261 2.013s' kPa 34.95 85.44 202.91I' kPa 17.45 33.04 68.21Shear Resistance Angle degs 17.56 17.56 17.56Cohesion c' kPa 7.40 7.40 7,40

Mal( Effective Principle Stress RatioAxial Strain 2.478 2.618 2.711Axial Stress kPa 34.89 66.09 136.42Cor. Deviator slress kPa 34.89 66.09 136.42Effeclive Major Siress kPa 52.39 118.49 271.12Effective Minor Stress kPa 17.50 52.40 134.70Effective Stress Ratio 2.994 2.261 2.013s' kPa 34.95 85.44 202.91l' kPa 17.45 33.04 68.21

(;"'-(I)

a:0;-xoril-V>;gc:~iii"Q)"0

!Ii1!!~-'<~IT:I-

"'"<Vx'"'f;

(f)0(')

s:a:0I-< ....a: 00 0(]) ~« <J:)

..J 0.,- usw '"

a,E<V

~C

'" '"if 0

E i Shearing"0 "0'" .,... :>o e'" Q.~ Q.

<.> <

4



Stage 3Stage 2Stage 1Specimen Details

Job Ref. Slope DynamiCSJob Locahon SidestrandBorehole 0 0 0sample No. STS STS ST5Depth m 0.15 0.15 0.15Date 20/0412001 20/04/2001 20/04/2001

Shearing Stage

Slope Dynamics Project - Sidestrand, ST5Multi-stage CIU Triaxial test

90,-------:-----------,----------------...,

-+-Stage 1"""'-Stage2-,-Slage3

I,-+-Siage 1

"""'-Slage2i-.-Stage3

32.52\.5

Axial Strain (%)

0.5

I II

./~ I-, -

I

~ i --

/~y~

70~----

80

160

oo

20

140

<U 1200-

""';; 100<I>eiii 80

o7ii 60:;

'"o 40

0;- 600-~

! 50::l...~ 40 t-------=:::;~~~~~;:=--+-.-..<==::::::==::===~----~ 30

to0C-OlIl:0)

"<Iif0-Ci)

~c

"~<IlOl"tl

~to

"0---'4:

~0::...""to.~Via

"s::0::0fo-« t"-Il: '"0 '"CD ~-I: <L>

~ ~w C\J

cDE:g

'"j? '"ij: 0

20 .....::...----,

10 -t------+-------,-------.-----..-----.'----------i

32.521.S

Alrtal Strain (%)

0.5O.l...-----+-----+------I-------------r-----I

o

5




Job Ret Slope DynamicsJob Location SidestrandBorehole 0 0 0Sample No. STS ST5 ST5Depth m 0.15 0.15 0.15Dale 20/0412001 20/0412001 20/04/2001

Shearing Stage

,--Slage 1

--Slage2

--Stage 3

-+-Slage 1I__Slage2 :

•--.- Sla~e~_:

3

3002.50

251.5

Axial Strain (%)

tOO \50 200

Normal EHective Stress (kNJm')

50

0,5

I

,

----

~,

----,.

~ -~

~~ I \~

--r Y \ r \oo

O+-----...,....-----...,..------,-------r------+------

°

Slope Dynamics Project - Sidestrand, ST5Multi-stage CIU Triaxial test

160

140

3

05 -1----------------7-----,-------+------,

20

3,5 ,-----------,--------;-----------,-------,

~

~ 2,5 +---------

~

iii 2r--==z~~~~11i;:;,~ 1,5 1----,;QF"'~=___""'""'~-----------------r_--------J.t...~;:;..ffi

_ \20~E

Z \00~

,.-------------

~00-0>0:Vi;c.,.;...~"\'!lii4>"0

0!:'l

'""0---'<l:X~lr...<C

'";<-~iJJa(!)

s:a::0...<l: ""n: 0

g 0~

j w0

..,-: <0UJ N

'"E'" ~"~ tou:: a

6




Job Ref. Slope DynamicsJob Location SideSlrandBorehole 0 0 0Sample No. STS STS ST5Depth m 0.15 0.15 0.15Dale 20/0412001 20/0412001 20104,12001

Shearing Stage

Slope Dynamics Project - Sidestrand. STSMulti-stage CIU Triaxial test

Normal Etlective Stress (kNlm2)

-, -

I

-Slage I I--Slage2

-Stage3!

300

I

I

250200

/150

--- c-----

160

_ 140

~\20Z

~

'" 100'" - -eiii

80<0G)J::

60In -tG)

~

U 40G)

~:t:.W 20

'J (0

0 50 100

l:00-lDrr:!il"<Iit--(/')

:;;c<IIZ,U;Q)..,~'"'"---'«X«a;t--""'"-;:;-~l=-(/')a~a:0~ t-o: 00 0CD ~« <.l)

:co! 0(0

W N

<>iEttl

0;c:.sl '"u:: a

7



Stage 3Stage 2Stage 1

Job Ref. AldbroughJob LocationBoreholeSample No. ALD1 ALD1 ALDI

Depth m 0.15[3.8 m bglJ O. 15 [3.B m bgl) 0.15 [3.B m bgl]

Dale 19/08/04 19/08/04 19108104Disturbed 1 Undisturbed undis undis undis

.,; iti Specimen DetailS~ roCl Cl

>- >.0 ~

~ ~ Description of Specimen.Y. 6~ ! Upper grey Till [Withemsea Till Member, Holderness Formation)

Initial Specimen ConditionsHeight mm 195.20 189.03 183.64Diameter mm 103,50 102.22 102.97

Area mm2 8413.38 8207.01 B327.41Volume em) 1642.29 1551.37 1529.24Mass 9 3525.70DIY Mass 9 3080.75

Density Mg/m3 2.15 2.27 2.31

DIY Density Mg/m3 1.88MOisture Content % 12.62Degree of Saturation %

Speciftc Gravity kN/m3

(assumed/measured)

Moisture Content % 12.86

DenSity Mglm3 0.00 0.00 0.00DIY Density Mglm3

Cl-'<t:"'£Ol~o

15n~

'"to'C--'<t:X«a:l--

'"'"><~iiJCI~ Final Specimen Conditions((

ol--<l: ra: 0o 0

~ :z::;l ~UJ N


Post-test

,,,,

,

Failure mode




c0Q.(\)

a:v;><Ci--'«:;0-J:.Ol:::>0

15-0

~'"a;

"0~

~x«cr:....'"'"~oS(j)

0

~a::(2« ....a: 0~ 0CD ~

~<D!2

W <DC\J

'"E'"c '"~ ;;;u:: a

Job Aef. AldbroughJob Location 0Borehole 0 0 0sample No. Al.D1 ALDI ALD1Depth m 0.15 (3.8 m bgl) 0.15 [3.8 m bglJ 0,15 (3.8 m bgl)Date 19/08/04 19/08/04 19/08/04

est etupDale started 15/05/06 15/05/06 15/05106Date FmishedTop DraIn Used y y yBase Drain Used y y ySIde Drains Used y y yPressure System NumberCell Number

SaturationCell Pressure Incr. kPa 2.10 17.60 9.10Back Pressure Incr. kPa 0.80 19.50 4.40Differential Pressure kPa 5.50 9.50 13.30Final Cell Pressure kPa 9.00 38.60 49.00Final Pore Pressure I<Pa 6.00 30,50 42.00Final B Value 0.50 0.83 0.50

ConsolidationEffective Pressure kPa 0,90 34.50 67.70Cell Pressure kPa 317.40 299.70 348.20Back Pressure kPa 316.50 265.20 280.50Excess Pore Pressure kPa 255.40 256.00 257.00Pore Pressure at End kPa 4.50 5.30 5.80

Consolidated Volume cm3 1551.37 1529.24 1497.15Volumetnc Strain 0.018454493 0.004755799 0.006993911Consolidated Height mm 191.60 188.13 182.35


Vol. Compressibility m2/MN 0.84396 0.98396 0.71610

Consolidation Coel. m~/yr,

2



Stage 1 Stage 2 Stage 3Specimen DetailsJob Ref. AldbroughJob Location 0Borehole 0 0 0Sample No. ALD1 ALD1 ALD1Depth m O. 15 [3.8 m bgl] 0.1 5 [3.8 m bgl] 0.15 (3,8 m bgl)Dale 19/08/04 19/08/04 19/08/04

Consolidation Stage

--+- Stage 1 I_Sltlge2

,...........Sl8.ge3

7060

1!X>0

l_

soSquare-root Time (min)

30 40


200 10

0

10

20

~30

~ 40Cb

'"<:

'" 50-.&:.(J

4>60E

:3'0> 70

80

90

tOO

2000

1500

t 1000c~<;;0-

500.~

0~:3 0/I)

'"e 10a.f -5000a.

·1000

-1500

{;C.0>a:7i>".a-l<t":£OlOJ0.i5

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3




Job Ret. AfdbroughJob Location 0Borehole 0 0 0sample No. ALDI ALD1 ALD1Deplh m 0.15 [3,8 m bgl] 0.15 [3.8 m bglJ 0.15 [3.8 m bgl)Date 19108104 19/08/04 19/08/04

eanng

Initial Cell Pressure kPa 299.5 349.2 449.2Initial Pore Pressure kPa 256.5 256 257.1Rate at Slrain %/hour 6.147479508 6.348145861 6.534505131

Max Deviator StressAxial Strain 1.332 2.337 3.455Axial Stress I<Pa 37.75 94.31 191.77Cor. Deviator stress I<Pa 37.75 94.31 191.77EHective Major Stress I<Pa 57.65 139.71 305.47EHective Minor Stress kPa 19.90 45.40 113.70EHective Stress Ratio 2.897 3.077 2.687S' kPa 38.77 92.56 209.59I' kPa 18.87 47.16 95.89Shear Resistance Angle degs 26.44 26.44 26.44Cohesion c' kPa 3.76 3.76 3.76

Max Effective Principle Stress RatioAxial Strain 1.332 2.337 3.455Axial Stress kPa 37.75 94.31 191.77Cor. DeViator stress kPa 37.75 94.31 191.77EHec\lve Major Stress kPa 57.65 139.71 305.47Effective Minor Stress kPa 19.90 45.40 113.70Effective Suess Ratio 2.897 3,077 2.687s' kPa 38.77 92.56 209.59l' kPa 18.87 47.16 95.89

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4


Consolidated Undrained Triaxial Compression TestBS 1377: Part 8: 1990

Stage 1 Stage 2 Stage 3Specimen DetailsJob Ref. AldbroughJob Location 0Borehole 0 0 0Sample No. ALD1 ALD1 AL01Depth m 0.15 [3.8 m bgl] 0.1 5 [3.8 m bgl] 0.15 (3.8 m bgl)Dale 19/08/04 19/08/04 19/08/04

Q) Q)

~ ~a 0

Shearing Stage

400I I I

350 1--- --+- I-

300

~., -e"-~ 250

f ........-Stage t::J

~ 200 ___ Stage?

~ ---.- Stllge_~0-.. 150 I:50-

100

SO

00 0,5 \ 5 2 2.5 3 3,5 4

Axial Strain ('Yo)

t::00.

'"0:7i)X

0....l<C:;;0>:>015"t:l

~<i"0....l<t:

~a:~

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250

200

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, I ,

1I

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I

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I

I 2150,5 I 15 2 3 3:5I

IAxial Strain (%j

--+-Stllge 1___ Slage2

--.-Stage3

5




Job Ref. AldbroughJob Location 0Borehole 0 0 0Sample No. ALDI ALD1 ALD1Depth m 0.15 [3.8 m bgl) 0.15 [3.8 m bgl) 0.15 [3.8 m bgl)Date 19/08/04 19/08/04 19/08/04

350300tOO t50 200 250

Normal Effective Stress (kNlm1

Shearing Stage

;,.. >..0 .0

'0 '0 3.5.,'" """ ~u

'".s::. 0.(.) <{ 3

.~<ii0: 2,5

'"'"~

e0 iii -+-S18901 i"" ~(I)

II: _518ge21Vi .;:;

>< .!: \ 5 --'-Slage3Q ~-'

~<{::>' U.s::.rn .,:l ~0 LLI.0

" 0.5·§;!ll

'""...J 0<tX 0 0.5 1.5 :! 2.5 3 35 4~a:: Axial Strain (%)l-

""'";:(.~jjj0~ \80s:a::2 160~ .....cr: 00 0III ~ 140:3 (£l

0

"'" <0 1-LlJ '" c- 120

~ I --Slagel~ 100 ---- - ----r- --Stag02

;" ...E II) --5Iag03., ~c: ilj iii 80~ 01u::: 0 ~.,

.s::. 60·(/l

6




Job Ref. AldbroughJob Location 0Borehole 0 0 0Sample No. ALD1 ALD1 ALD1Depth m 0.15 [3.8 m bgl] 0.15 [3.8 m bgl] 0.15 [3.8 m bgl]Dale 19/08/04 19/08104 19/08/04

Shearing Stage

-- ---

,$

'-L f

~

\ I, " ./

; .J


00.

'"a:<il><;::;...J<l:~D>::>0.0..,5'"(;j"0...J<l:X~a:!;;..:~if,ClCJs::a:8« "-II: 00 0CD ~;5 ~UJ N

0;E'"c (l)

~ ;;;u:: Cl

180

tOO

N 140EZ~ t20

:&~ tOOif,...'"~ 80(/)...~ 60U.!!i:ii 40

20

oo 50 tOO t50 200 250 300

I 'Ii

'-Stagel

-Stage 2

-Stage 3

350

7

Documents

Triaxial strength tests on till samples from the Slope Dynamics