上海重塑粘性土的直剪特性研究

The Shearing Properties of Remoulded Clay Soils in the Shanghai Region

上海地区浅层广泛分布的淤泥质粉质粘土、淤泥质粘土和粘土具孔隙比大、含水量高、压缩性大、强度低等特点,容易对工程造成严重不良影响。对这三种土重塑样的直剪特性进行了系统研究,试验方法包括固结快剪和固结慢剪,剪切过程中量测剪切位移和竖向压缩量,剪切结束后量测了破坏面上的土样含水率。结果显示,固结慢剪试验中土样均硬化,剪切位移达6mm时仍未破坏;而固结快剪试验中,除粉质粘土外另两类土在0.2mm的位移下就达到剪切强度。通过试验得到了剪切应力与剪切位移关系、剪缩变形量和抗剪强度参数等。结合试验结果,对粉质粘土与粘土的不同结构导致直剪特性的差异进行了分析讨论。可为上海重塑土的结构及力学特性研究提供依据和借鉴。

In the Shanghai Region,shallow soil layers consist mainly of mixed silt-clay,mixed clay,and clay soils.These types of soil are characterized by certain qualities,including having a large void ratio,high water content,high compressibility,and low shear strength.These soils and their geotechnical qualities therefore influence construction and engineering considerations.This paper investigates the shearing properties of these three remoulded soils by using both consolidated quick shearing and slow shearing tests.During the tests,shearing displacement,vertical compression,and water content on the failure plane,were all measured.The results show that all soils hardened in the consolidated quick test using a vertical compression of 6 mm.The same was true using the consolidated slow test and a vertical compression of 0.2 mm,with the exception of the silt-clay soil.Through the study,relationships between shearing stress,shearing displacement,the amount of deformation,and the parameters of shearing strength were investigated.The results of the test were combined and differences in shearing properties of the soils were analyzed and discussed.These results provide useful information regarding the structural and mechanical characteristics of remoulded soil in the Shanghai region.