工程地质学报2018，Vol.26Issue(6)：1490-1498,9.DOI:10.13544/j.cnki.jeg.2017-519
颗粒破碎对钙质砂的应力-应变及强度影响研究
THE STUDY ON STRESS-STRAIN-STRENGTH BEHAVIOR OF CALCAREOUS SAND WITH PARTICLE BREAKAGE
摘要
Abstract
The crushing of particles is one of the important factors that cause change of the sand mechanical properties, in particular the fragile material calcareous sand. This paper aims to further understand the effect of particle crushing on the stress-strain and shear strength of calcareous sand. It carries out a series of triaxial sheartests on calcareous sand with different relative densities under different confining pressures. It analyzes the particle size distribution curves of calcareous sand samples before and after tests. It discusses the particle breakage rules of calcareous sand as well as their influencing factors. Through triaxial tests the stress-strain curve of the calcareous sand is obtained. The relationship between relative density and particle crushing, confining pressure and particle crushing, and the effect of particle crushing on stress-strain and shear strength of calcareous sand were analyzed by introducing Hardin 's relative breaking ratio Br. The results show that with the increase of confining pressure, the increment of particle shrinkage decreases gradually until the crushing reaches an upper limit. Then the confining pressure and relative density have little effect on the particle crushing. The influence degree of relative density on particle crushing is less than confining pressure. Sliding friction can bring about the stress increase to a limit state.The particle crushing result in the stress cannot reach the state. In the experimental condition, particles are less broken under low confining pressure and the relative motion form among particles is slip, so the stress-strain curve is soften strain type. Under high confining pressure the particles crushing becomes serious and occurs throughout the shear process. So the stress-strain curve is hardening strain type. Particle breakage makes the volume gradually change from the dilatancy to the shrinkage. The more serious the breakage is, the more obvious the shrinkage is.Under low confining pressure the strength of calcareous sand is mainly provided by dilatancy and interlocking. Due to the serious particles breakage under high confining pressure, the dilatancy disappears and the interlocking decreases, so the peak friction angle decreases and the shear strength reduces.关键词
钙质砂/三轴试验/颗粒破碎/强度Key words
Calcareous sand/Triaxial test/Particle breakage/Strength分类
天文与地球科学引用本文复制引用
陈火东,魏厚振,孟庆山,王志兵,冯铮..颗粒破碎对钙质砂的应力-应变及强度影响研究[J].工程地质学报,2018,26(6):1490-1498,9.基金项目
中国科学院战略性先导科技专项(XDA19060301) （XDA19060301）
中国科学院青年创新促进会(2015272) （2015272）
国家自然科学基金(41877260,41877267) （41877260,41877267）
广西岩土力学与工程重点实验室课题(11-KF-07)资助. （11-KF-07）
