Penetration testing in the UK : proceedings of the geothecnology conference organized by the Institution of civil engineers and held in Birmingham on 6-8 july 1988

352 Pages·1989·26.927 MB·English

by  Institute of Civil Engineers

Penetration testing in the UK
Penetration testing in the UK
Proceedings of the geotechnology conference organized by the
Institution of Civil Engineers and held in Birmingham on
6-8 July 1988
Thomas Telford, London
Conference sponsored by the Institution of Civil Engineers, the British
Geotechnical Society, the Midland Geotechnical Society and the Midland Branch
of the Institution of Civil Engineers
Organizing Committee: I. K. Nixon (Chairman), K. W. Cole, C. Craig,
S. Thorburn, T. R. M. Wakeling
British Library Cataloguing in Publication Data
Penetration testing.
1. Engineering geology
I. Institution of Civil Engineers
624.1/51/0287
ISBN 978-07277-1377-3
First published 1989
© The Institution of Civil Engineers, 1988,1989, unless otherwise stated.
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Papers or other contributions and the statements made or the opinions expressed therein are published on the
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its publication does not necessarily imply that such statements and or opinions are or reflect the views or
opinions of the ICE Council or ICE committees.
Published for the Institution of Civil Engineers by Thomas Telford Ltd, Thomas Telford House, 1 Heron Quay,
London E14 9XF.
Contents
Keynote address. A. C. MEIGH 1
Report on ISOPT-1. B. A. LEACH 9
Session 1. Standard penetration test
Introduction to Papers 1-9
Parti. F.M.JARDINE 23
Part 2. M. A. STROUD 29
1. SPTs in chalk: a rethink. R. N. MORTIMORE and D. JONES 51
2. Diagenetic alteration and micro-structural characteristics of sands:
neglected factors in the interpretation of penetration tests.
M. E. BARTON, M. R. COOPER and S. N. PALMER 57
3. Contribution to the chalk classification by means of visual and
penetration techniques. S. PERELBERG, D. G. GUY and
D. A. FERNANDO 61
4. Penetration testing in the design of foundations for large silos on
Lias Clay. F. G. BUTLER 65
5. Water tank foundations on alluvial soil-subsoil explorations.
A. V. JALOTA, S. C. JAIN and D. K. JOSHI 71
6. The standard penetration test and foundation movements on
glacial tills and weak rocks. J. M. W. HOLDEN and M. YILMAZ 77
7. The application of the SPT in weak sandstone and mudstone rocks.
R. P. THOMPSON and B. A. LEACH 83
8. The use of the standard penetration test for the design of bored
piles in the Keuper Marl of Cardiff. N. S. KILBORN, G. TREHARNE
and V. ZARIFIAN 87
9. The effect of water on SPT results in sand. M. S. MOJABI and
G. G. THOMAS 93
Discussion on Papers 1-9. S. THORBURN, P. K. ROBERTSON, K. W. COLE,
R. P. THOMPSON, A. D. BARLEY, M. E. BARTON M, . JAMIOLKOWSKI,
J. M. W. HOLDEN, T. R. M. WAKELING, G. THOMPSON,
L. THREADGOLD, D. M. TONKS, F. M. JARDINE, I. K. NIXON,
R. N. MORTIMORE, P. R. VAUGHAN, J. M. PAISLEY, M. J. TURNER,
J. M. REID, B. A. LEACH, K.-J. MELZER, I .L. WHYTE, N. P. LEE,
R. McNICOL and M. S. MOJABI
Session 2. Dynamic probing
Introduction to Papers 10-13.1. K. NIXON 105
10. Dynamic soundings in site investigations: some observations and
correlations. D. M. TONKS and I. L. WHYTE 113
11. The use of continuous dynamic probing in ground investigation.
G. B. CARD and D. P. ROCHE 119
12. Application of dynamic cone penetrometer testing in East Anglia.
P. J. CEARNS and A. McKENZIE 123
13. Factors governing the use of continuous dynamic probing in UK
ground investigation. R. D. SCARFF 129
Discussion on Papers 10-13.1. K. NIXON, C. N. EDMONDS, I. L. WHYTE,
K.-J. MELZER, A. McKENZIE, A. C. MEIGH, J. J. M. POWELL,
M. J.TURNER, M.SCOTT and G.B. CARD 133
Session 3. Piezocone penetration test
Introduction to Papers 14-19. G. T. HOULSBY 141
14. Interpretation of piezocone results in overconsolidated clays.
A. J. LUTENEGGER and M. G. KABIR 147
15. Interpretation and use of the piezocone test in UK clays.
J. J. M. POWELL, R. S. T. QUARTERMAN and T. LUNNE 151
16. Finite element analysis of cone penetration. S. M. WILLSON,
B. W. IMS and I. M. SMITH 157
17. The use of the piezocone test for monitoring the strength of rock
paste. P. A. BRAITHWAITE, G. S. GHATAORA and J. S. COUTTS 161
18. Piezocone tests in a china clay tailings dam. T. R. M. WAKELING 167
19. The use of piezocone in the design of a deep basement in London
Clay. M. M. LONG and N. J. O'RIORDAN 173
Discussion on Papers 14-19. P. K. ROBERTSON, J. J. M. POWELL, K. BEEN,
G. T. HOULSBY, M. JAMIOLKOWSKI, M. BATTAGLIO, D. BRUZZI,
A. J. LUTENEGGER, A. C. MEIGH, Z. M. NYIRENDA, G. C. SILLS,
C. H. ADAM, T. R. M. WAKELING, A. J. BOND, M. G. JEFFERIES and
P. R. VAUGHAN 177
Session 4. Basic cone penetration test
Introduction to Papers 20-30. D. W. BIDDLE 189
20. The static cone penetration test as lithology identifier.
N. A. TRENTER and C. MILLER 193
21. Characterization of sandfills with the cone penetration test.
M. G. JEFFERIES, B. T. ROGERS, K. M. GRIFFIN and K. BEEN 199
23. Interpretation of piezocone soundings in clay — a case history.
R. G. CAMPANELLA, J. P. SULLY and P. K. ROBERTSON 203
24. Investigation of cone penetration test in British clay carried out by
the Building Research Establishment 1960-86. A. MARSLAND and
J. J. M. POWELL 209
25. Interpretation of material state from the CPT in sands and clays.
K. BEEN, J. H. A. CROOKS and M. G. JEFFERIES 215
26. The use of cone penetration tests in glacial till. M. J. D. DOBIE 219
27. Penetration testing in glacial till. P. J. BAKER and R. GARDENER 223
28. An example of the use of cone penetration testing in the design of
underground structures and temporary works in cohesive soils.
J. M. REID and K. W. TURNBULL 227
29. The application of statistical methods to the interpretation of cone
tests and use in subsequent design. B. W. IMS and F. E. TOOLAN 231
30. Determination of representative CPT-parameters. H. HARDER and
G. VON BLOH 237
31. The use of 'penetrators' for the measurement of the undrained
shear strength of soft marine clays. T. J. FREEMAN 241
32. Piezocone measurements with four pore pressure positions.
G. C. SILLS, R .E. MAY, T. HENDERSON and Z. NYIRENDA 247
33. The implications of observed deformations during cone
penetration. P. K. CHEN and R. H. BASSETT 251
Discussion on Papers 20-33. M. J. D. DOBIE, H. ERWIG, A. C. MEIGH,
J. J. M. POWELL and N. A. TRENTER 257
Session 5. Pressuremeter, dilatometer and other developments
Introduction to Papers 34-44. C. CRAIG 265
34. The interpretation of the Marchetti dilatometer test in UK clays.
J. J.M.POWELL and I. M. UGLOW 269
35. Shear wave velocity measurements during penetration testing.
P. HEPTON 275
37. Interpretation of pore pressure measurements from advanced cone
penetration testing. E. SKOMEDAL and J. MARTYN BAYNE 279
38. Tests in a small calibrated chamber: experimental and numerical
analysis. AL MUKHTAR MUZAHIM 285
39. The use of cone penetration testing to obtain environmental data.
M. R. HORSNELL 289
41. Comparison between results from flat dilatometer and self-boring
pressuremeter tests. B. G. CLARKE and C. P. WROTH 295
42. Stiffness of sands from CPT, SPT and DMT — a critical review.
G. BALDI, R. BELLOTTI, N. GHIONNA and M. JAMIOLKOWSKI 299
44. High pressure dilatometer tests in Upper Chalk at Hull.
A. R. WOODLAND, C. L. NG and D. CORKE
Discussion on Papers 33-44. B. G. CLARKE, S. MARCHETTI,
P. K. ROBERTSON, D. CORKE and G. T. HOULSBY 313
Closing address. Future trends for penetration testing.
M. JAMIOLKOWSKI and P. K. ROBERTSON 321
Appendix 1. Cone penetration test: international reference test
procedure. ISOPT-1 343
Appendix 2. Standard penetration test: international reference test
procedure. ISOPT-1 357
Appendix 3. Dynamic probing: international reference test
procedure. ISOPT-1 361
Appendix 4. Demonstration competition. I. K. NIXON 367
Papers 22, 36, 40 and 43 were withdrawn
Keynote address
A. C. MEIGH, OBE, DSc(Eng), FICE, Woodward-Clyde Consultants
INTRODUCTION screw-shaped point (Figure 1) and the above
The interpretation of the results of penetration outline of the test procedure, are enough to
tests is mainly empirical, and in some cases tell us that it is unlikely that anyone will
entirely empirical. That is to say, deriving produce a theoretical model. The test is
from experiment and observation rather than from entirely empirical.
theory. Nevertheless, as pointed out by Wroth I do not wish to denigrate the WST; it appears
(1988), any correlation between results of in- to be a very useful tool in some ground
situ tests and soil properties should be: conditions, particularly in the preliminary
stages of an investigation for determining the
(i) based on physical insight; depth and thickness of strata.
(ii) set against a theoretical background; Anyone faced with interpreting the results of
and WSTs should study carefully the Working Party
(iii) expressed in dimensionless form. Report to ISOPT I by Bergdahl, Broms and
Muromachi and the Conference paper by Bergdahl
I would add only that the dimensionless forms and Ottossan.
should be satisfactory practically as well as
theoretically. I will touch on this point
later.
I intend shortly to make a brief overview of 034-0'
the various types of penetration test, taking Dimensions in mm
into account the preceding comments. This
overview will be from the viewpoint of the
practising geotechnical engineer. But first a
comment about standardisation. You may know
that for some years the ISSMFE have been working
towards proposals for standardisation of certain
aspects of penetration testing. At ISOPT 1,
held in Florida in March of this year, working
parties presented reports which included for
each type of test a proposed International
Reference Test Procedure (IRTP), and Bernard
Leach will be outlining these. An empirical
approach can only be successful if the test
procedures are standardised to a large degree.
It is of prime importance that these reference
test procedures are followed.
THE WEIGHT SOUNDING TEST
I will start with a test about which I need
say least, the weight sounding test (WST). As
far as I know it has not been used in this
country; it is extensively used in Sweden,
*New point 0
Norway, Finland and Denmark, where it is the
35-0 ± 0-2mm
most commonly used penetration testing method. Worn point 0
To my surprise, I now learn that it has also 32-0 ± 0-2mm
been used in Poland, Hungary, Czechoslovakia,
Japan, Singapore, the Philippines and Algeria.
So we may meet it on our travels.
In the WST, the point is penetrated by the
application of weights added in stages, without
rotation of the probe, to maintain a constant
rate of penetration, and when it will not
penetrate further under a weight of 1 kN it is
rotated and the number of half-turns per 0.2m of Fig. 1. Weight sounding test; screwpoint
penetration is recorded. The peculiar (Bergdahl et al, 1988)
Penetration testing in the UK. Thomas Telford, London, 1989
KEYNOTE ADDRESS
THE STANDARD PENETRATION TEST Table 1. Approximate corrections to measured N
Equally empirical, and likely to remain so, is values (Skempton, 1986)
the Standard Penetration Test (SPT). Over the
years it has been extensively used and
extensively criticised: extensively used in this Rod length: >10 m 1.0
country because it suits our geology and is 6-10 m 0.95
convenient for use in light cable percussion 4-6 m 0.85
boring and in rotary drilling; criticised here 3-4 m 0.75
and elsewhere for a number of reasons:
(i) its vulnerability and sensitivity to Standard sampler 1.0
faulty operation; US sampler without liners 1.2
(ii) the differences in methods of driving
the sampler; and
(iii) difficulties in interpretation. (How Borehole diameter: 65-115 m 1.0
did one choose between the 150 mm 1.05
multiplicity of methods of determining 2 00 mm 1.15
allowable bearing capacity in
cohesionless soils?)
But now, recent advances are giving the SPT a
new lease of life. Over the last ten years or In the IRTP, under "Boring Methods and
so, much research has gone into factors which Equipment", it is stated that "in situations
affect the amount of energy delivered to the rod where comparisons of SPT results are important,
system; type of hammer, release system, anvil calibrations will be made to evaluate the
weight. We now talk in terms of rod energy efficiency of the equipment in terms of energy
ratio, ER , the ratio of the energy delivered to transfer; and again, in the working party
the rods to the theoretical free-fall energy of report, it is recommended that "in situations
the hammer. By means of dynamic load cells it where comparisons of SPT results are important
is now possible to measure the delivered energy it is considered that energy input should be
(Schmertmann and Palacios, 1979). The measured and methods of calibration have been
importance of normalising SPT blow counts to a presented for guidance". Somewhat lacking in
standard rod energy ratio has been recognised, force. Surely, comparison is always important;
and Seed et al (1984) have proposed a ratio of it is the essence of the empirical approach.
60 per cent. Hence Skempton (1986), following Seed, has
recommended that measured SPT values should be
N, = N ER /60 normalised to a rod energy ratio of 60 per cent.
oun r
Based on the study of a number of sites and some
(Incidentally the Pilcon and Dando equipment laboratory test data, Skempton. also recommends
used in the UK both have a rod energy ratio of certain corrections to be applied to measured N
about 60%.) values; for rod length where it is less than
The proposed IRTP presented at ISOPT 1 deals 10m, for borehole diameter where it is greater
with boring methods and equipment. This should than 115mm, and for the use of the US sampler
go a long way towards removing differences in without a liner. (Table 1) In the IRTP there
procedure and eliminating unsuitable features, is no correction for rod length, although in the
although the SPT will still be somewhat calibration procedure a correction is included
vulnerable to operator error. The IRTP does not based on the ratio of mass per unit length of
deal with interpretation, as one might expect. the rod to mass of the hammer. The IRTP also
In the Working Party report, which includes limits the borehole diameter to between 63.5 and
the IRTP, the importance of the rod energy ratio 150mm but makes no correction for diameter. It
is recognised, and a method of calibration for makes no correction for use of the US sampler
rod energy ratio is included. Unfortunately, without liner. (Although not contemplated in
the IRTP lacks force in this respect; under the IRTP, the liner is frequently omitted from
"reporting of results", it is required to the US sampler at present).
report, inter alia:
6) dimensions and weights of drive rods D =.O 15 35 50 65 85 100%
r
7) type of hammer and release mechanism or
method Very Loose Medium Dense Very
8) height of free fall, and loose dense
16) Calibration results, where appropriate*: (#1)60=0 15 25 42 58
This is followed by an explanatory note
"Calibrations of drive rods and hammer This is derived from the Terzaghi-Peck classi-
assemblies, where appropriate,* would normally fication. For D > 0-35 it corresponds to
r
be carried out for each rig and separately from
the investigation work. They would be
applicable to a particular project, based on
the personnel and equipment involved". Fig. 2. Average correlation between SPT blow
count and relative density; NC sands (Skempton,
* Underlining added. 1986)
2
MEIGH
Table 2. Effect of ageing (Skempton, 1986) where N is greater than 15 (Terzaghi and Peck,
1948), and in gravel or sandy gravel N is
multiplied by 1.25. In assessing settlement,
Age: years 'Veo'V adjustments are made for foundation shape and
thickness of the sand layer. A time factor is
included and an allowance is made for the effect
-2
Laboratory tests 10 35 of overconsolidation.
Recent fills 10 40 Burland and Burbidge is based on the analysis
2
Natural deposits >10 55 of 200 case histories. It is empirical; but a
reading of Burbidge's MSc thesis on which the
paper depends, reveals that it is firmly based
on physical insight (Wroth's first requirement).
Skempton has revised the Terzaghi and Peck However, Burland and Burbidge predates Rod
classification of relative density (Figure 2). Energy Ratio; and it includes no corrections for
This applies to medium sands; for fine sands, N borehole diameter, rod length or use of the US
is reduced in the ratio 55/60, and for coarse sampler without liner. We should encourage
sands N is increased in the ratio 65/60. Professor Burland to find another post graduate
Finally, Skempton found an effect of ageing on student to revise Burland and Burbidge taking
the SPT values on sands, giving typical results these factors into account. Hopefully, this
for a NC sand (Table 2). would reduce the spread between upper and lower
There is much more of interest in Skempton's limit values of the compressibility factor I .
paper, including the effects of The use of the SPT in weak and weathered rocks
overconsolidation. The paper is recommended was pioneered in this country in the 1950's. It
reading for all concerned with the use and is a major topic in Session 1.
interpretation of the SPT.
On the question of interpretation of SPT DYNAMIC PROBING
results, another milestone has been the Dynamic probing (DP) is probably the oldest
introduction by Burland and Burbidge (1985) of a method of penetration testing in foundation
method of estimating, from SPT results, the engineering. From information provided to the
settlement of foundations on cohesionless soils. ISSMFE working party on dynamic probing, it
This should replace the previous methods. It appears that it is used only occasionally in
follows on from a paper by Burland et al (1977). this country. Of the four categories of probe,
I still find their plot of settlement/applied only two are used here; light (DPL), mass 10kg
pressure against breadth of footing (Figure 3) or less, and superheavy (DPSH), mass greater
useful as an indicator of whether settlement is than 60 kg. We have no national recommended
a problem or not. procedure or standard.
Burland and Burbidge's method is a direct One bogey which has affected the use of DP in
method, proceding from average N to a the past is the problem of skin friction on the
compressibility factor I . N is corrected for rods. This has been overcome in the IRTP by
very silty and fine sands below the water table
Tentative upper limit
20- for loose sands
1-0-
0-8_
0-6_ Upper limit
for medium
/dense sand
0-2.
Upper limit for
CO 0-08. dense sand
<D
0-06.
CL
e
pli 0-
QL.
ro
CZ 0-02_
0-01,
0-1 0-2 U 0-6 0-8 1 2 L 6 810 20 60 80100 200
Breadth,fl(m)
Fig. 3. Observed settlement of footings on sand of various relative densities (after Burland, Broms
and de Mello, 1977)