Development of pore pressures in quasi-static penetration tests in sensitive clay

1982 ◽  
Vol 19 (2) ◽  
pp. 124-138 ◽  
Author(s):  
Marius Roy ◽  
Michel Tremblay ◽  
François Tavenas ◽  
Pierre La Rochelle
Keyword(s):  
Penetration Test ◽  
Sensing Element ◽  
Cone Penetration ◽  
Pore Pressures ◽  
Soil Deposits ◽  
Sensitive Clay ◽  
Rate Of Dissipation ◽  
Excess Pore Pressures ◽  
Penetration Tests ◽  
Static Cone Penetration Test

The static cone penetration test is a valuable tool for the investigation of soil deposits but its potential may be further improved in the future if the pore pressures generated around the cone tip during the penetration are measured.A new sounding instrument called a piezocone was built at Université Laval to investigate the magnitude, effects of rates of penetration, and rate of dissipation of the excess pore pressures according to the location of the porous stone on the apparatus.The magnitude of the pore pressures induced during driving is a maximum at the cone tip and then decreases along the shaft as measured by porous stones located behind the cone tip. Induced pore pressures at the tip are independent of the rate of penetration, but a very small rate effect may influence the pore pressures measured behind the cone tip. The results show that the use of the ratio u/qc for soil characterisation may be considered only after adoption of standards regarding the location of the sensing element and the rate of penetration.The new sounding tool models the penetration of a single pile relatively well and its use is suggested for the study of pore pressures during the penetration of piles and their dissipation with time.

Evaluation of excess pore pressures and drainage conditions around driven piles using the cone penetration test with pore pressure measurements

1990 ◽  
Vol 27 (2) ◽  
pp. 249-254 ◽  
Author(s):  
P. K. Robertson ◽  
D. J. Woeller ◽  
D. Gillespie
Keyword(s):  
Pore Pressure ◽  
Large Diameter ◽  
Cone Penetration Test ◽  
Pressure Measurements ◽  
Penetration Test ◽  
Cone Penetration ◽  
Pore Pressures ◽  
Clayey Silt ◽  
Excess Pore Pressures ◽  
Excess Pore

Large-diameter steel pipe piles were driven as part of the foundations for the Alex Fraser Bridge near Vancouver, British Columbia. The piles penetrated through a normally consolidated marine clayey silt. As part of the geotechnical studies a multipoint piezometer was installed close to the pile group. A cone penetration test with pore pressure measurements (CPTU) was performed adjacent to one of the piles shortly after driving. During the CPTU through the clayey silt deposit, dissipation tests were performed to evaluate the pore pressures around the nearby pile. The CPTU results are compared with the pore pressures recorded at the multipoint piezometer, allowing for differences in radial distance from the piles. Excellent agreement was obtained between the CPTU and multipoint piezometer data, both showing large excess pore pressures around the piles. The CPTU dissipation data were also analyzed to evaluate the time required for dissipation of excess pore pressures around the piles. The upper half of the clayey silt deposit was inter bedded with thin sand and silt layers. The CPTU data showed that the thin sand layers were sufficiently large in extent to allow rapid dissipation of the pore pressures due to cone penetration but were not of sufficient extent to allow dissipation of the excess pore pressures from the much larger diameter piles. Key words: in situ, piles, pore pressures, CPT.

scholarly journals Effectiveness of resistivity cone penetration tests in salt-treated highly sensitive clay

2017 ◽  
Vol 170 (3) ◽  
pp. 173-184 ◽  
Author(s):  
Tonje Eide Helle ◽  
Michael Long ◽  
Steinar Nordal ◽  
Per Aagaard
Keyword(s):  
Cone Penetration ◽  
Cone Penetration Tests ◽  
Highly Sensitive ◽  
Sensitive Clay ◽  
Penetration Tests

Development of a quasi-static piezocone apparatus

1982 ◽  
Vol 19 (2) ◽  
pp. 180-188 ◽  
Author(s):  
Marius Roy ◽  
Michel Tremblay ◽  
François Tavenas ◽  
Pierre La Rochelle
Keyword(s):  
Pore Pressure ◽  
Excess Pore Pressure ◽  
European Symposium ◽  
Failure Zone ◽  
Conical Part ◽  
Penetration Test ◽  
Cone Penetration ◽  
Penetration Testing ◽  
Pore Pressures ◽  
Filter Arrangement

The European Symposium on Penetration Testing (ESOPT) held in Stockholm in 1974 has contributed to the improvement of interpretation methods and also to the standardization of the cone penetration test (CPT). In recent years, the importance of the pore pressures generated during cone penetration has led to the development of new sounding equipment to measure this parameter in addition to the usual cone penetration parameters.The apparatus developed at Université Laval consists of a conical tip equipped with a filter in order to measure pore pressure and cone resistance simultaneously during the penetration. In addition, since the conical tip is detachable, five types of tips were used in the study in order to vary easily the position of the pore pressure pick-up and to study the pattern of pore pressures generated at or behind the cone tip.The results show that the filter arrangement has a significant effect on the registered magnitude of excess pore pressure. The generated pore pressures are highest when they are measured in the failure zone of the intact clay, i.e., when the filter arrangement is located on the conical part of the tip.

In situ sampling, density measurements, and testing of foundation soils at Duncan Dam

1994 ◽  
Vol 31 (6) ◽  
pp. 927-938 ◽  
Author(s):  
Howard D. Plewes ◽  
V. Sitham Pillai ◽  
Michael R. Morgan ◽  
Brian L. Kilpatrick
Keyword(s):  
Soil Sampling ◽  
Frozen Soil ◽  
Engineering Properties ◽  
Energy Calibration ◽  
Penetration Test ◽  
Cone Penetration ◽  
Field Investigations ◽  
Sample Disturbance ◽  
Penetration Tests

As part of the B.C. Hydro Dam Safety Review of Duncan Dam, a comprehensive two-phased program of field and laboratory investigations was carried out between 1988 and 1992 to evaluate the potential for liquefaction of the foundation soils during an earthquake. The initial screening level phase 1 field investigations comprised basic soil sampling, standard penetration tests, and cone penetration tests to determine the spatial distribution of the foundation soils beneath the dam and to characterize the basic engineering properties of the soil units. A screening study using Seed's liquefaction assessment method indicated that soil unit 3c consisting of uniform fine-grained sand would be susceptible to liquefaction. The phase 2 investigations consisted of detailed and careful soil sampling to obtain high-quality in situ samples of the unit 3c sand for laboratory triaxial and simple shear tests. Samples were obtained using a conventional fixed piston sampler and a specially modified Christensen double core barrel sampler. The samples were frozen to minimize sample disturbance during handling and transport. Ground freezing was also conducted using liquid nitrogen, and the frozen soil was sampled using a CRREL core barrel. Borehole density logging was performed to assess the quality and level of disturbance of the soil samples. This paper discusses the procedures and results of the phases 1 and 2 field investigations. Key words : standard penetration test, cone penetration test, geophysical logging, energy calibration, soil sampling, freezing.

scholarly journals Estimating bearing capacity using static cone penetration test at Banda Aceh area (northern tip of Sumatra)

2021 ◽  
Vol 1087 (1) ◽  
pp. 012025
Author(s):  
B Setiawan ◽  
T Saidi ◽  
M Sungkar ◽  
H Gunawan ◽  
A Yulianur ◽  
...  
Keyword(s):  
Bearing Capacity ◽  
Cone Penetration Test ◽  
Penetration Test ◽  
Cone Penetration ◽  
Banda Aceh ◽  
Static Cone Penetration Test
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