Analysis of self-boring pressuremeter (SBPM) and Marchetti dilatometer (DMT) tests in granite saprolites

2000 ◽  
Vol 37 (4) ◽  
pp. 796-810 ◽  
Author(s):  
F Schnaid ◽  
J AR Ortigao ◽  
F M Mántaras ◽  
R P Cunha ◽  
I MacGregor
Keyword(s):  
Site Investigation ◽  
Friction Angle ◽  
Soil Parameters ◽  
Residual Soil ◽  
Residual Soils ◽  
In Situ Tests ◽  
Cemented Sand ◽  
Fundamental Parameters ◽  
Analysis Technique

This paper presents the analyses of the results of the site investigation programme carried out at the Kowloon Bay site in Hong Kong. The tests consisted of self-boring pressuremeter (SBPM), Marchetti dilatometer (DMT), and laboratory tests carried out in a granite saprolite, which can be described as a lightly cemented sand. The purpose of this research project is to stimulate the development of methods to interpret data obtained from tests in residual soils. In particular, the work aims to evaluate the analyses of the SBPM data through a curve-fitting technique. Both the loading and unloading portions of the SBPM curve were analysed and the results compared with those from other tests. The advantage of this analysis technique is the possibility of constructing a theoretical curve that reproduces a pressuremeter test from which a set of fundamental parameters can be derived, namely the friction angle, cohesion intercept, lateral stress, and shear modulus. The DMT proved to be a reliable tool that yielded good soil parameters at a small fraction of the cost of the other in situ tests.Key words: residual soil, in situ tests, pressuremeter, Marchetti dilatometer.

Assessment of the range of variation of Nγ from 60 estimation methods for footings on sand

2013 ◽  
Vol 50 (7) ◽  
pp. 793-800 ◽  
Author(s):  
Edgar Giovanny Diaz-Segura
Keyword(s):  
Friction Angle ◽  
Standard Penetration Test ◽  
Estimation Methods ◽  
Penetration Test ◽  
In Situ Tests ◽  
Vertical Loading ◽  
Simplified Method ◽  
Bearing Capacity Factor ◽  
Range Of Variation

The range of variation of the bearing capacity factor, Nγ, was assessed using 60 estimation methods for rough footings on sand subjected to static vertical loading. The influence on the Nγ values of the use of correlations for the estimation of the friction angle, [Formula: see text], derived from in situ tests was also assessed. The analysis shows a marked dependency on the methods used to determine Nγ, showing differences for the same [Formula: see text] values of up to 267% between estimated values. Uncertainty in the estimation of [Formula: see text], due to the use of correlations with in situ tests, leads to a range of variation for Nγ higher than that seen using the 60 estimation methods. Finally, given the regular use of the in situ standard penetration test (SPT) on sands, and based on a series of analyses using finite elements, a simplified method in terms of the SPT N-values is proposed for estimation of Nγ in footings on sands.

scholarly journals Influence of the structure on the collapse potential and shear strength of a residual soil in the semiarid region of Northeast Brazil

2021 ◽  
Vol 337 ◽  
pp. 01003
Author(s):  
Valteson da Silva Santos ◽  
Allan B.Silva de Medeiros ◽  
Romário S.Amaro da Silva ◽  
Olava F. Santos ◽  
Osvaldo de Freitas Neto ◽  
...  
Keyword(s):  
Shear Strength ◽  
Expansive Soils ◽  
Friction Angle ◽  
Semiarid Region ◽  
Original Structure ◽  
Residual Soil ◽  
Residual Soils ◽  
Strength Parameters ◽  
Effective Measure ◽  
Two Samples

In the last decades, several engineering works have been developed in the Northeast of Brazil, a region marked by the occurrence of collapsible and expansive soils. This work aimed to characterize and study the behavior of two samples of residual soils collected in the municipality of Salgueiro-PE regarding their collapse potentials and shear strength parameters, in natural and disturbed conditions, evaluating the influence of the applied vertical stresses and the structural arrangement in these properties. The results obtained showed that the two samples analyzed show collapsible behavior, however, the observed potential for collapse was lower after the original structure arrangement was undone. From the direct shear strength tests, the strength parameters of the two soils were obtained, which pointed effective friction angle close to 30° and cohesive intercept close to 0 kPa. The destructuring of the samples did not cause a considerable variation in these parameters. Thus, it was possible to conclude that for these samples the microstructure has a predominant influence on the occurrence of collapsibility, but does not have the same relevance on the shear strength, such that the material’s destructuring can be considered as an effective measure to reduce the potential collapse.

Interpretation of overconsolidation ratio from in situ tests in Recent clay deposits in Singapore and Malaysia

1991 ◽  
Vol 28 (2) ◽  
pp. 210-225 ◽  
Author(s):  
M. F. Chang
Keyword(s):  
Site Investigation ◽  
Test Methods ◽  
In Situ Tests ◽  
Stress History ◽  
Overconsolidation Ratio ◽  
Clay Deposits ◽  
Preconsolidation Pressure ◽  
Pressure Stress ◽  
Sample Disturbance

The stress history as indicated by the profile of overconsolidation ratio (OCR) of a soil deposit is one of the most dominant factors that influence the engineering behaviour of the soil. Its assessment, which is traditionally based on the laboratory oedometer test, is not often satisfactory. The problem arises from inevitable sample disturbance and the high cost of a detailed investigation. These difficulties can be overcome by the use of in situ tests. The field vane test, the piezocone test, and the dilatometer test are three such methods that provide indirect means for the estimation of the OCR for clay deposits. A number of empirical correlations are available for this purpose. Calibration of these correlations against results of site investigation in Singapore and Malaysian marine clays reveals the usefulness of these test methods in profiling the OCR for Recent clay deposits. Key words: clay, in situ test, overconsolidation ratio, preconsolidation pressure, stress history.

scholarly journals Determination of p-y curves for offshore piles based on in-situ soil investigations

2018 ◽  
Vol 219 ◽  
pp. 05003
Author(s):  
Kamila Międlarz ◽  
Lech Bałachowski
Keyword(s):  
Field Tests ◽  
Soil Parameters ◽  
Lateral Loads ◽  
Cohesionless Soils ◽  
In Situ Tests ◽  
Soil Stiffness ◽  
Soil Response ◽  
Direct Design ◽  
Offshore Piles

Offshore piles are subjected to complex loads with considerable lateral component. The pile-soil response to lateral loads can be described with the p-y method. For a given depth the load–deflection relationship is built to simulate the surrounding soil stiffness. This state-of-art paper presents a brief discussion of determination methods for the p-y curves using a standard approach based on the soil parameters derived from laboratory and in-situ tests or directly from field tests. The basic relationships for both cohesive and cohesionless soils are discussed. The advantage of direct design methods to describe the p-y curve relies in the reduction of necessary laboratory tests.

Nonlinear Analysis of Settlement for Cohesionless Soil Foundations Based on In Situ Tests

2012 ◽  
Vol 204-208 ◽  
pp. 107-114
Author(s):  
Ren Ping Li ◽  
Jie Liu
Keyword(s):  
Limit State ◽  
Standard Penetration Test ◽  
Summation Method ◽  
Tangent Modulus ◽  
Cohesionless Soil ◽  
Soil Parameters ◽  
Ultimate Limit State ◽  
In Situ Tests ◽  
Loading Test

A new technique is proposed to calculate nonlinear settlement for foundation by using the data of plate loading test (PLT) and standard penetration test (SPT) or other in-situ tests. Firstly, hyperbolic curve is fitted out from the data of PLT and the tangent modulus equation of soil is established, then correctional tangent modulus (CTM) equation is established by feedback adjusting according to the fitting curve of PLT; Secondly, the CTM equations of different stratified soil at different depth are determined by soil parameters of SPT or other in-situ tests according to linear correlation; Finally, the nonlinear settlement of foundation is calculated by the layerwise summation method. An engineering application of settlement prediction for the largest oil tank in China indicated that this technique is able to calculate the entire nonlinear settlement from initiation to ultimate limit state and obtain accurate results, and it is suitable for cohesionless soil with high permeability.

In situ tests in Brasília porous clay

1996 ◽  
Vol 33 (1) ◽  
pp. 189-198 ◽  
Author(s):  
J A.R Ortigao ◽  
R P Cunha ◽  
L S Alves
Keyword(s):  
Low Cost ◽  
Laboratory Data ◽  
Design Parameters ◽  
Residual Soils ◽  
In Situ Testing ◽  
In Situ Tests ◽  
Deformation Parameters ◽  
Strength And Deformation ◽  
Plate Loading

An in situ testing programme was carried out in 1992 aimed at obtaining design parameters for the construction of the Brasília Underground line, Brazil. The top layer of soil consisted of an unsaturated and collapsible soft porous clay layer 5–30 m thick followed by residual soils from slate and interlayered metasiltsones and quartzites. A series of Marchetti dilatometer (DMT) logging tests results were comapred with Ménard pressuremeter (PMT) and horizontal plate loading (PLH) tests, as well as laboratory tests on block samples. In situ stresses, strength, and deformation parameters were obtained for the porous clay. The DMT yielded very good results: excellent repeatability, low cost, and results that agree with other in situ tests and laboratory data. Key words: porous clay, in situ testing, dilatometer, pressuremeter.

New equipment for densification of granular soils at depth

1990 ◽  
Vol 27 (2) ◽  
pp. 167-176
Author(s):  
R. G. Campanella ◽  
R. Hitchman ◽  
W. E. Hodge
Keyword(s):  
Field Testing ◽  
Independent Study ◽  
Soil Parameters ◽  
Granular Soils ◽  
In Situ Tests ◽  
River Sand ◽  
University Of British Columbia ◽  
A Site ◽  
The Phoenix

An in situ densification probe that employs the novel technique of simultaneous vibration and dewatering has been developed by Phoenix Engineering Ltd. to compact deep, loose, granular soils. It is believed that pumping water out of the soil during the densification process offers improved densification capability over systems operating with vibration alone. An independent study was undertaken by the In-Situ Testing Group at the University of British Columbia to evaluate the performance of the Phoenix system.A field testing programme was conducted at a site in Vancouver where hydraulic sand fill overlies a natural silt and then medium Fraser River sand. Characterization of the site and evaluation of the densification treatment process were achieved using in situ tests. Changes to soil parameters due to densification treatment were examined, taking into account the modification of stresses brought about by the vibro-drainage process. The study investigated the degree of densification achieved, the value of concurrent drainage, the zone of influence of a single compaction probe, and group effects. The study also compares the performance of the Phoenix machine with that of other vibrocompaction equipment. Key words: in situ, densification, soils, granular, probe, vibratory, drainage, compaction, R&D.

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