摘要
珊瑚礁沉积的钙质砂与石英砂的物理力学性质有较大差别。对取自南海岛礁的钙质砂进行了单次往返环剪试验以分析钙质砂的抗剪强度特性,试验中考虑了相对密实度和竖向应力对结果的影响,并与相同级配和试验条件下的石英砂进行对比分析。结果表明:钙质砂正向剪切时应力-位移曲线为软化型,具有明显的残余强度特性,而反向剪切时则表现为硬化型,正向和反向剪切强度基本一致;石英砂正向剪切和反向剪切均表现为软化型。钙质砂正向剪切和反向剪切残余强度与峰值强度的比值在0.75～0.93之间;石英砂正向剪切和反向剪切残余强度与对应峰值强度的比值在0.89～0.96之间。相同级配和试验条件下,钙质砂残余强度均大于石英砂,且强度比值基本保持在1.05～1.3之间。在100、200 kPa竖向荷载作用下,钙质砂0.5～2.0 mm的颗粒发生了破碎,破碎率分别为4%和6%。
Calcareous sands deposited on coral reefs are different from the quartz sands in their physical and mechanical properties. In this paper, we conducted ring shear tests with a single cycle on the calcareous sand sampled from the South China Sea. The effects of relative density and vertical stress were compared with the quartz sand under the same particle size and test conditions. The results indicate that shear stress and displacement curves of calcareous sand in forward ring shear tests tend to soften with a clear residual strength, while that tend to harden in reversed ring shear tests. The strength in forward and reversed ring shear tests are equal. The curves of the shear stress with displacement of quartz sand in forward and reversed ring shear tests tend to soften. The ratio of residual strength to peak strength of calcareous sand ranges from 0.75 to 0.93, while that of quartz sand ranges from 0.89 to 0.96. Residual strength of calcareous sand is higher than that of quartz sand with same particle size distribution and test conditions and the ratio ranges from 1.05 to 1.3. The particle of calcareous sand, in the size of 0.5 mm to 2 mm, occurs breakage under the vertical loading of 100 kPa and 200 kPa, and breakage percentages of particle are 4% and 6% respectively.
作者
黄宏翔
陈育民
王建平
刘汉龙
周晓智
霍正格
HUANG Hong-xiang;CHEN Yu-min;WANG Jian-ping;LIU Han-long;ZHOU Xiao-zhi;HUO Zheng-ge(Key Laboratory of Ministry of Education for Geomechanics and Embankment Engineering, Hohai University, Nanjing, Jiangsu 210098, China;College of Civil and Transportation Engineering, Hohai University, Nanjing, Jiangsu 210098, China;Design and Research Bureau of Navy Engineering, Beijing 100070, China;College of Civil Engineering, Chongqing University, Chongqing 400045, China;China Railway Shidai Architectural Design Institute Co., Ltd., Wuhu, Anhui 241001, China)
出处
《岩土力学》
EI
CAS
CSCD
北大核心
2018年第6期2082-2088,共7页
Rock and Soil Mechanics
基金
国家自然科学基金面上项目(No.51379067
No.51679072)
国家自然科学基金重点国际(地区)合作研究项目(No.51420105013)
教育部长江学者创新团队发展计划(No.IRT-15R17)~~
关键词
钙质砂
环剪试验
残余强度
颗粒破碎
calcareous sand
ring shear tests
residual strength
particle breakage
