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.

scholarly journals Development of Fragility Curves for Piping and Slope Stability of River Levees

Water ◽  
2021 ◽  
Vol 13 (5) ◽  
pp. 738
Author(s):  
Nicola Rossi ◽  
Mario Bačić ◽  
Meho Saša Kovačević ◽  
Lovorka Librić
Keyword(s):  
Slope Stability ◽  
Fragility Curves ◽  
Safety Margin ◽  
Water Levels ◽  
Flood Event ◽  
Soil Parameters ◽  
Design Code ◽  
A Site ◽  
Insight Into

The design code Eurocode 7 relies on semi-probabilistic calculation procedures, through utilization of the soil parameters obtained by in situ and laboratory tests, or by the means of transformation models. To reach a prescribed safety margin, the inherent soil parameter variability is accounted for through the application of partial factors to either soil parameters directly or to the resistance. However, considering several sources of geotechnical uncertainty, including the inherent soil variability, measurement error and transformation uncertainty, full probabilistic analyses should be implemented to directly consider the site-specific variability. This paper presents the procedure of developing fragility curves for levee slope stability and piping as failure mechanisms that lead to larger breaches, where a direct influence of the flood event intensity on the probability of failure is calculated. A range of fragility curve sets is presented, considering the variability of levee material properties and varying durations of the flood event, thus providing crucial insight into the vulnerability of the levee exposed to rising water levels. The procedure is applied to the River Drava levee, a site which has shown a continuous trend of increased water levels in recent years.

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.

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.

The 2003 R.M. Hardy Lecture: Soil parameters for numerical analysis in clay

2006 ◽  
Vol 43 (2) ◽  
pp. 187-209 ◽  
Author(s):  
J Graham
Keyword(s):  
Constitutive Modeling ◽  
Laboratory Tests ◽  
Soil Parameters ◽  
In Situ Tests ◽  
Design Problems ◽  
Time Effects ◽  
Stiff Clays ◽  
Numerical Tools ◽  
Wetting Time

Engineers in geotechnical practice work on increasingly complex problems with increasingly powerful numerical tools. Effective solutions to design problems need good information about the site and parameters (or functions) that describe how the soil will behave under the proposed loadings. These loadings can include heating, drying or wetting, time effects, and chemical changes as well as the more common structural loads. This paper outlines issues that need to be considered when laboratory tests are used to produce soil properties for use in numerical analyses. The focus is on soft to moderately stiff saturated clays. Similar considerations for in situ tests, stiff clays, and sands are not considered.Key words: clay, testing, characterization, properties, constitutive modeling.

Design parameters of granular soils from in situ tests

2020 ◽  
pp. 65-94
Author(s):  
Michele Jamiolkowski ◽  
Diego C.F. Lo Presti ◽  
Francesco Froio
Keyword(s):  
Design Parameters ◽  
Granular Soils ◽  
In Situ Tests

Investigation of small- to large-strain moduli correlations of normally consolidated granular soils

2021 ◽  
Vol 58 (1) ◽  
pp. 1-22
Author(s):  
Ibrahim Lashin ◽  
Michael Ghali ◽  
Mahmoud N. Hussien ◽  
Mohamed Chekired ◽  
Mourad Karray
Keyword(s):  
Large Strain ◽  
Small Strain ◽  
In Situ Stress ◽  
Soil Parameters ◽  
Physical Parameters ◽  
Granular Soils ◽  
Shear Wave Velocities ◽  
Settlement Behavior ◽  
Constrained Modulus

The establishment of correlations between the small-strain shear modulus (Go) and other soil parameters (such as the oedometer constrained modulus, Moedo) at large deformations constitutes an important step toward more precise modeling of soil deformation behavior. In this study, the shear wave velocities (Vs) of 22 different granular soils of various physical characteristics were measured experimentally using the piezoelectric ring-actuator technique (P-RAT) incorporated in the conventional oedometer cell. For each sample tested, the development of Moedo with the development of relative density (Id), as well as the void ratio (e), was recorded. Then, the obtained Vs and Moedo/Go trends were correlated to the physical parameters of the tested granular soils with the development of e and Id. A practical application employing the achievements in geotechnical engineering design was also evaluated. Based on the proposed correlations, geotechnical designers can easily estimate in situ stress–settlement behavior from the predicted Moedo and Id values using simple in situ measurements.

scholarly journals A comparative theoretical-experimental analysis of settlements of shallow foundations on granular soil

2010 ◽  
Vol 8 (2) ◽  
pp. 135-143
Author(s):  
Nebojsa Davidovic ◽  
Zoran Bonic ◽  
Verka Prolovic ◽  
Biljana Mladenovic ◽  
Dragoslav Stojic
Keyword(s):  
Reinforced Concrete ◽  
Experimental Analysis ◽  
Shallow Foundations ◽  
Granular Soil ◽  
Granular Soils ◽  
Prediction Methods ◽  
Test Accuracy ◽  
In Situ Tests ◽  
Foundation Design

The paper presents a brief description of experiment within the research project 'Theoretical and experimental analysis of interaction of shallow reinforced concrete foundations and soil for the purpose of improvement of national regulations and implementaation of Eurocode system' where in situ tests of a series of reinforced concrete foundation footing were performed, by loading until failure. As a rule, methods for calculation of shallow foundations settlement on granular soils overestimate the expected settlement, and underestimate soil bearing capacity, which results in a conservative foundation design. In order to test accuracy and reliability of the different settlements prediction methods, a comparative analysis of settlements calculated using these methods and those measured during experiment, was performed.

In situ tests in a sand dune

1991 ◽  
Vol 28 (2) ◽  
pp. 304-309
Author(s):  
J.-M. Konrad
Keyword(s):  
Steady State ◽  
Relative Density ◽  
Field Data ◽  
Sand Dune ◽  
Field Testing ◽  
Field Investigation ◽  
Density Field ◽  
Empirical Correlations ◽  
In Situ Tests

A field testing program using an electric piezocone penetrometer (CPTU) and a flat dilatometer (DMT) probe was carried out in a sand dune. The analysis of the field data in terms of relative density using current empirical correlations showed that significant differences were obtained at this site. It is suggested that any empirical correlation between relative density and CPT or DMT data obtained from calibration chambers should only be used for a sand that has the same slope of the steady-state line as the sand used in the calibration tests. Key words: sand, in situ density, field investigation, piezocone penetrometer, flat dilatometer, steady state.

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