Experimental and theoretical investigation of the high‐pressure, undrained response of a cohesionless sand

Abstract

Key in predicting stability in sands during dynamic events is gaining a fundamental understanding of the physics of its deformation and failure at high pressures. In this paper are reported results of an experimental investigation into the high-pressure (up to 700 MPa) mechanical response of Quikrete sand. During all triaxial compression tests, the material exhibited hardening up to failure while both compressibility and dilatancy regimes of the volumetric response were observed. Furthermore, the transition from compressibility to dilatancy was found to be highly dependent on confining pressure. By performing triaxial compression tests with several creep stages followed by unloading-reloading cycles, the time influence of the overall response was detected. Using the experimental data, a new model that captures both compressibility and dilatancy has been developed. Comparison between model predictions and data showed that the proposed model describes well the main characteristics of the high-pressure response of sand. Experiments required for the calibration of the model are as follows:A minimum of four CTC tests at varying confining pressures, 3 , in the stress range of the particular application for the material. Each experiment should include at least three loading-creep-unloading-reloading cycles. Hydrostatic compression test including at least three loading-creep-unloading-reloading cycles. Calibration procedureA linear regression software, developed and distributed by SYSTAT, called 'TableCurve ® 2D' version 5.01 was used. The software is available at www.systat.com. Additionally, the TableCurve ® 2D allows for evaluation of the first and second derivatives allowing the model developer to assess continuity of any function chosen to represent the material behavior.

An experimental investigation of the micromechanics of Eglin sand

“…Luo et al [17] studied the dynamic compressive behaviour of a finer fraction of Eglin sand under very high confinement using a long split Hopkinson pressure bar at high strain rates for constitutive modelling and mesoscale simulations. Martin and Cazacu [18] investigated the mechanical behaviour of Eglin sand up to high pressures in the triaxial cell, studying its creep behaviour and developing a model based on their experimental results.…”

High-pressure compressibility and shear strength data for soils

“…At high pressures (σ 3 = 310 MPa), Murphy (1971) used a triaxial cell to show that an increase in the mineral hardness of a soil results in an increase in shear strength and a reduction in compressibility. Martin and Cazacu (2013) also used a triaxial cell to characterise the strength and elastic properties of a quartz sand at high pressures (σ 3 ≤ 300 MPa), and successfully defined a linear failure surface and stressdependent elastic moduli. Both compression and dilation were observed during deviatoric loading in these experiments.…”

“…Both compression and dilation were observed during deviatoric loading in these experiments. Recent triaxial testing approaches (Martin et al 2013, Barr et al 2016a) have begun to explore the shear response of soils at very high strain rates: further comparison with high-pressure quasi-static data is required to investigate whether existing models of shear behaviour hold under this extreme loading. This paper demonstrates the use of a high-pressure multi-axial test apparatus to characterise the quasi-static compressibility and failure surface of quartz sands to pressures of 800 MPa and 400 MPa, respectively.…”