摘要
花岗岩残积土在赣南安定高速公路沿线分布广泛,研究其物理力学特性对当地公路建设以及可能引发的边坡失稳的防治具有重要意义。对现场采取的残积土土样进行室内基本土工实验,实验结果表明,塑性指数为14,将其定名为粉质黏土;比重为2.64,天然含水率及最优含水率分别为23.44%和20.03%。以TRA三轴剪切渗流仪为实验平台,采用抽气饱和、水头饱和与反压饱和的方式,对花岗岩残积土原状样和重塑样进行三轴固结不排水剪切实验,结果如下:原状样的抗剪强度参数为c=15.17 k Pa、φ=13.66°,重塑样的抗剪强度参数为c=10.82 k Pa、φ=17.58°;原状样的内聚力较重塑样略大,而摩擦角较重塑样略小,应力-应变曲线表明原状样在各级围压下存在应变转型,而重塑样则始终表现为应变硬化。根据实验的分析结果,提出花岗岩残积土边坡在工程实践中应采取的相关措施,并指出实验过程中存在的问题。
Granite residual soil is widely distributed along the Anyuan-Dingnan Highway in southern Jiangxi Province,the study of its physical and mechanical characteristics is of great significance for local highway construction and the control of instable slope. The basic indoor soil test was performed on the residual soil samples collected at site,the results show that: The plasticity index is 14,belongs to silty clay. The specific gravity is 2. 64. The natural and optimum water content are 23. 44% and 20. 03%,respectively. Taking TRA triaxial shear seepage instrument as the experimental platform,by means of pumping saturation,head saturation and back pressure saturation,the triaxial consolidated undrained shear tests are carried out,including undisturbed samples and remolded samples of granite residual soil. The results indicate that the shear strength parameters of the undisturbed sample are c = 15. 17 k Pa,φ = 13. 66°,and those of the remolded sample are c = 10. 82 k Pa,φ = 17. 58°. The cohesion of the undisturbed sample is slightly larger than that of the remolded sample,the friction angle is slightly smaller than that of the remolded sample. Stress-strain curves show that the undisturbed sample has strain transformation at all levels of confining pressure,the remolded sample always exhibits strain hardening. Based on the experimental results,propose some relative measures in the engineering practice of granite residual soil slope and point out the existing problems of the experiment.
出处
《科学技术与工程》
北大核心
2018年第4期115-120,共6页
Science Technology and Engineering
基金
江西省交通运输厅科技计划(2015c0026)
国家自然科学基金(41272306)资助
关键词
花岗岩残积土
物理力学特性
固结不排水剪切实验
抗剪强度
应力-应变曲线
granite residual soil
physical and mechanical characteristic
consolidated undrained shear test
shear strength
stress-strain curve
