直剪条件下钙质砂强度及颗粒破碎  

Strength and Particle Breakage of Calcareous Sand Under Direct Shear Test

作　　者：王青 侯贺营 康鑫睿 李天翔 姜朋明[1,2] 周爱兆 WANG Qing;HOU He-ying;KANG Xin-rui;LI Tian-xiang;JIANG Peng-ming;ZHOU Ai-zhao(School of Civil Engineering and Architecture, Jiangsu University of Science and Technology, Zhenjiang 212110, China;School of Civil Engineering, Suzhou University of Science and Technology, Suzhou 215009, China)

机构地区：[1]江苏科技大学土木工程与建筑学院,镇江212110 [2]苏州科技大学土木工程学院,苏州215009

出　　处：《科学技术与工程》2022年第15期6240-6247,共8页Science Technology and Engineering

基　　金：国家自然科学基金(51979128)。

摘　　要：钙质砂的主要成分是碳酸钙,由于其特殊成因,钙质砂具有孔隙特征。为了深入研究粒径、含水率及剪切速率对钙质砂强度及颗粒破碎特性的影响,在不同粒径、含水率和剪切速率等因素下对钙质砂进行直剪试验。试验结果表明:①钙质砂的抗剪强度和内摩擦角与粒径之间存在正相关的关系,小粒径(<1.0 mm)情况下,粒径和竖向压力不再是影响颗粒破碎的主要因素,大粒径(>1.0 mm)情况下,颗粒破碎程度出现剧增现象,粒间咬合和约束的存在是此现象的主要原因。②粒间水膜和颗粒损伤的存在,导致钙质砂的内摩擦角随着含水率的升高逐渐减小,含水率和内摩擦角之间呈指数函数关系。相对破碎随着含水率的升高先减小后增大。③颗粒在剪切过程中存在翻滚现象,但过大的剪切速率会使得颗粒直接从中间位置剪切,钙质砂的内摩擦角随着剪切速率的增大呈现先减小再增大的现象,相对破碎则是随着剪切速率的增大呈现先减小后增大的趋势。The main component of calcareous sand is calcium carbonate.Due to its special genesis,calcareous sand has the characteristics of multi porosity.In order to further study particle size's possessions,water content and shear rate on the particle breakage flavours and strength of calcareous sand,direct shear tests were executed on calcareous sand with different particle sizes,water contents and shear rates.The results show these as follows.The shear strength and internal friction angle of calcareous sand increase with the increase of particle size.In the case of small particle size(<1.0 mm),particle size and vertical pressure are no longer the main factors affecting particle breakage.In the case of large particle size(>1.0 mm),the degree of particle breakage increases sharply,and the existence of interparticle bite and constraint is the main reason for this phenomenon.The existence of particle damage and intergranular water film leads to the gradual decrease of calcareous sand's internal friction angle with water's rise content,and the relationship between internal friction angle and water content is an exponential function.There is a rolling phenomenon of particles in the shear process,but too large shear rate will make the particles shear directly from the middle position.The internal friction angle of calcareous sand first decreases and then rises with the rise of shear rate,and the relative crushing first decreases and then rises with the rise of shear rate.

关 键 词：钙质砂 直剪试验 抗剪强度 内摩擦角 颗粒破碎 

分 类 号：TU443[建筑科学—岩土工程]