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Despite the various approaches in the literature adopted for analysing cone penetration test (CPT), determination of the initial horizontal stress and relative density of a sandy soil during this test has not been tackled yet. In order to propose a new method in this regard, a numerical study of CPT has been performed and the predicted results have been compared with several databases of comprehensive calibration chamber tests. The penetration mechanism has been then fully investigated by presenting different kinds of outputs for the surrounding soil. Finally, an innovative procedure has been suggested for estimating the initial horizontal stress and relative density during performing CPT in... 

Separation of the effects of initial horizontal stress and relative density on cone tip resistance in sandy soils has been a complicated issue for many years. In order to overcome this problem, a numerical modeling of CPT which has been verified by calibration chamber tests, has been used in this paper to achieve a reliable analytical solution. The analytical solution has resulted in two relationships for sleeve friction and cone tip resistance in terms of the initial conditions of sandy soil. Based on the presented solution, the initial horizontal stress and relative density can be determined according to CPT measurements. © 2017 Elsevier Ltd  

Despite the various approaches in the literature adopted for analysing cone penetration test (CPT), determination of the initial horizontal stress and relative density of a sandy soil during this test has not been tackled yet. In order to propose a new method in this regard, a numerical study of CPT has been performed and the predicted results have been compared with several databases of comprehensive calibration chamber tests. The penetration mechanism has been then fully investigated by presenting different kinds of outputs for the surrounding soil. Finally, an innovative procedure has been suggested for estimating the initial horizontal stress and relative density during performing CPT in... 

Despite the various approaches in the literature adopted for analysing cone penetration test (CPT), determination of the initial horizontal stress and relative density of a sandy soil during this test has not been tackled yet. In order to propose a new method in this regard, a numerical study of CPT has been performed and the predicted results have been compared with several databases of comprehensive calibration chamber tests. The penetration mechanism has been then fully investigated by presenting different kinds of outputs for the surrounding soil. Finally, an innovative procedure has been suggested for estimating the initial horizontal stress and relative density during performing CPT in... 

The paper presents a numerical finite difference model of self-boring pressuremeter test (SBPM) using FLAC software. Different cavity expansion theories in sand have been compared to the results of numerical analyses carried out in this study. Limit pressure is believed to be used as a key parameter for the estimation of soil parameters from pressuremeter tests. In practice, SBPM tests are conducted up to 10–15% cavity strains, and the strain level associated with the limit pressure state is not reached. Therefore, determination of limit pressure usually needs extrapolation. In this paper, the authors suggest to use cavity pressure at 10% strain (P10) for the interpretation of in situ... 

In this study, a numerical finite difference model of self-boring pressuremeter test (SBPM) is performed. Limit pressure is believed to be a key parameter for estimation of soil parameters from pressuremeter tests, however; self-boring pressuremeter tests are practically conducted up to 10-15% strains, so determination of limit pressure usually needs extrapolation. For an alternative solution, it is recommended to consider cavity pressure corresponding to 10% strain (P10) for interpretation of soil parameters instead of limit pressure; therefore, more than 5000 numerical analyses of SBPM are carried out to correlate cavity pressure corresponding to 10% strain (P10) to sand parameters with... 

A numerical modeling procedure is presented to evaluate cone tip resistance in sand. The procedure involves a moving boundary simulating cone penetration. The soil is modeled as a Mohr-Coulomb elastic-plastic material with stress-dependent parameters. The procedure is verified by comparing predicted numerical values of cone tip resistance with published experimental measurements from calibration chamber tests. The selected database. consists of 59 calibration chamber tests on Ticino sand with different relative densities, overconsolidation ratios, stresses, and boundary conditions. Several applications of the modeling procedure are also presented. The computer program FLAC is used to carry... 

Surface settlement is considered as an adverse effect induced by tunneling in the civil projects. This paper proposes the use of the imperialist competitive algorithm (ICA) for predicting the maximum surface settlement (MMS) resulting from the tunneling. For this work, three forms of equations, i.e., linear, quadratic and power are developed and their weights are then optimized/updated with the ICA. The requirement datasets were collected from the line No. 2 of Karaj urban railway, in Iran. In the ICA models, vertical to horizontal stress ratio, cohesion and Young’s modulus, as the effective parameters on the MSS, are adopted as the inputs. The statistical performance parameters such as root... 

Surface settlement is considered as an adverse effect induced by tunneling in the civil projects. This paper proposes the use of the imperialist competitive algorithm (ICA) for predicting the maximum surface settlement (MMS) resulting from the tunneling. For this work, three forms of equations, i.e., linear, quadratic and power are developed and their weights are then optimized/updated with the ICA. The requirement datasets were collected from the line No. 2 of Karaj urban railway, in Iran. In the ICA models, vertical to horizontal stress ratio, cohesion and Young’s modulus, as the effective parameters on the MSS, are adopted as the inputs. The statistical performance parameters such as root... 

The casing-collapse hazard is one that drilling engineers seek to mitigate with careful well design and operating procedures. However, certain rock formations and their fluid pressure and stress conditions are more prone to casing-collapse risks than others. The Gachsaran Formation in south west Iran, is one such formation, central to oil and gas resource exploration and development in the Zagros region and consisting of complex alternations of anhydrite, marl and salt. The casing-collapse incidents in this formation have resulted over decades in substantial lost production and remedial costs to mitigate the issues surrounding wells with failed casing string. High and vertically-varying...