钙质砂剪切强度的单剪试验研究  

Study on the Shear Strength of Carbonate Sand by Single Shear Test

作　　者：卢川 李飒[2] 刘鑫[2] 苟乐宇 尹蒋松 Lu Chuan;Li Sa;Liu Xin;Gou Leyu;Yin Jiangsong(Tianjin Survey Design Institute Group Co.,Ltd.,Tianjin 300191,P.R.China;School of Civil Engineering,Tianjin University,Tianjin 300350,P.R.China)

机构地区：[1]天津市勘察设计院集团有限公司,天津300191 [2]天津大学建筑工程学院,天津300350

出　　处：《地下空间与工程学报》2024年第6期1904-1912,共9页Chinese Journal of Underground Space and Engineering

基　　金：国家自然科学基金(42072294);国家自然科学基金重大项目(51890911)。

摘　　要：岛礁土体地下空间的主要土质为钙质砂。通过对两种不同相对密实度的钙质砂试样进行的常体积和常应力条件下的单剪试验,以及具有相同级配的石英砂的对比试验,对钙质砂的抗剪强度进行了研究。结果表明:在相同的颗粒级配条件下,钙质砂具有高于石英砂的临界内摩擦角及低于石英砂的相变角和最大剪胀角的特性;钙质砂的最大剪胀角、相变角及临界内摩擦角均受颗粒破碎的影响,其中最大剪胀角及临界内摩擦角随着破碎的增加而降低,而相变角随着破碎的增加而增加。最后,将临界内摩擦角和剪胀角视为颗粒破碎的“效果角”,通过引入影响颗粒破碎的相对密实度,提出了基于现有评价方法的钙质砂最大内摩擦角的计算模型。The carbonate sand is the main soil material in the underground space of island reef soil.The shear strength of carbonate sand is studied by direct simple shear tests under constant volume and constant stress conditions on two kinds of carbonate sand with different relative density and by contrast tests on quartz sand with the same particle distribution gradation.The test results show that for the same particle size distribution,carbonate sand has a critical friction angle higher than that of quartz sand,its phase angle and maximum dilation angle lower than that of quartz sand.At the same time,the maximum dilation angle,phase angle and critical friction angle of carbonate sand are affected by particle breakage,of which the maximum dilation angle and critical friction angle decrease with the increase of breakage,while the phase angle increases with the increase of breakage.In this study,the critical friction angle and dilation angle are considered as the"effect angle"of particle breakage.By introducing the relative density that affects particle breakage,a calculation model for the maximum internal friction angle of carbonate sand based on the existing evaluation methods is proposed.

关 键 词：钙质砂 单剪试验 颗粒破碎 最大剪胀角 临界内摩擦角 

分 类 号：TU921[建筑科学—建筑设计及理论]