Traffic-load-induced dynamic stress accumulation in subgrade and subsoil using small scale model tests
Lian Sheng Tang,Hao Kun Chen,Yin Lei Sun,Qing Hua Zhang,Hua Rong Liao
Abstract
Under repeated loading, the residual stresses within the subgrade and subsoil can accelerate the deformation of the road structures. In this paper, a series of laboratory cyclic loading model tests and small-scale model tests were conducted to investigate the dynamic stress response within soils under different loading conditions. The experimental results showed that a dynamic stress accumulation effect occurred if the soil showed cumulative deformation: (1) the residual stress increased and accumulated with an increasing number of loading cycles, and (2) the residual stress was superimposed on the stress response of the subsequent loading cycles, inducing a greater peak stress response. There are two conditions that must be met for the dynamic stress accumulation effect to occur. A threshold state exists only if the external load exceeds the cyclic threshold stress. Then, the stress accumulation effect occurs. A higher loading frequency results in a higher rate of increase for the residual stress. In addition to the superposition of the increasing residual stress, soil densification might contribute to the increasing peak stress during cyclic loading. An increase in soil stiffness and a decrease in dissipative energy induce a greater stress transmission within the material.
Lian Sheng Tang — 1.) Department of Earth Science and Geological Engineering, Sun Yat-sen University, No. 135 Xingang Road West, Guangzhou 510275, Guangdong Province, China 2.) Guangdong Provincial Key Laboratory of Geological Processes and Mineral Resources Survey, Guangzhou 510275, China
Hao Kun Chen, Yin Lei Sun, Qing Hua Zhang and Hua Rong Liao — Department of Earth Science and Geological Engineering, Sun Yat-sen University, No. 135 Xingang Road West, Guangzhou 510275, Guangdong Province, China
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