Sharif Digital Repository

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  

A numerical modeling procedure was used to quantify calibration chamber size and boundary effects for cone penetration testing in sand. In the numerical analyses, chamber diameter and boundary conditions were varied to investigate the effects of chamber size and boundary conditions on cone tip resistance. These analyses show that, for loose sand, a chamber-to-cone diameter ratio of 33 is sufficient for the boundaries to have no influence on the cone tip measurements. However, for very dense sand, the numerical analyses show that the chamber-to-cone diameter ratio should be more than 100 to ensure that boundaries have no influence on cone tip measurements. Numerical analysis indicates that,... 

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... 

Liquefaction is one of the most serious geotechnical hazards that may cause irreparable and financial damages. Based on in-situ testing results, several methods have been developed to evaluate the liquefaction potential. Due to continuous and repeated records, the piezocone (CPTu) has gained wide acceptance among other in-situ tests in geotechnical practice. In this paper, a new approach is proposed for liquefaction potential evaluation based on CPTu results. The new approach is verified by ten CPTu soundings (case histories) derived from different sites. By analyzing the liquefied sites, an area on the soil classification charts was introduced in this paper, showing the soil types which are... 

A finite difference-based numerical model simulating the cone penetration process in unsaturated sands is presented. Mohr–Coulomb model (MCM) with simple modifications and Sun model (SM) were implemented to capture the unsaturated sand behaviour. It was shown that the cone tip resistance values resulting from the two models were fairly comparable. Predicted cone tip resistance values in dry, saturated and unsaturated sands using MCM were validated by the results of field and calibration chamber tests. Sensitivity analyses were performed, and the influence of parameters including relative density, mean effective stress and apparent cohesion due to suction on the tip resistance was... 

A numerical analysis is presented to model the cone penetration test (CPT) tip resistance in layered soil. Analyses are performed for two-layer soils composed of either sands with different relative densities or different materials (sand and clay). Parametric numerical modeling is used to determine the distance that a cone senses a new upcoming soil layer interface or a layer interface behind. Analyses are also carried out for a thin sand layer embedded in soft clay. It is seen that the full tip resistance may not be reached in thin stiff layers. This is especially true for penetration in thin dense sand layers interbedded in softer clay. A correction factor is suggested to correct the cone...