花岗岩残积土水-力相互作用特性研究

Hydro-Mechanical Interaction Characteristics of Granite Residual Soil

花岗岩残积土在我国东南部分布广泛,在降雨入渗作用下残积土边坡容易发生失稳破坏,研究其水-力相互作用特性对花岗岩残积土边坡的防护与治理具有重要的意义。采用瞬态脱湿与吸湿试验对花岗岩残积土的水-力相互作用特性进行研究。结果表明:花岗岩残积土原状样在脱湿条件下的进气值为3.07 kPa,在吸湿条件下的进气值为1.52 kPa;脱湿条件下获取的土样α~d、n^d、θ~d_s、K^d_s参数与吸湿条件下获取的α~w、n^w、θ~w_s、K^w_s参数存在一定差异性,这些参数的差异性决定了花岗岩残积土样水-力相互作用特性的不同;花岗岩残积土样的基质吸力和吸应力随体积含水率的增大而减小,土样的渗透系数随体积含水率的增大而增大;花岗岩残积土在相同体积含水率下,土样的干密度越大,进气值、基质吸力和吸应力越大,渗透系数越小。

The granite residual soil is widely distributed in the southeast of China.The residual soil slope is prone to instability and damage under the rainfall infiltration.The study of its hydro-mechanical interaction characteristics is of great significance to the protection and treatment of the granite residual soil slope.This paper conducts transient release and imbibition experiment to study hydro-mechanical interaction characteristics of granite residual soil.The results show that the influent value of granite residual soil under dehumidification condition is 3.07 kPa,and the influent value under hygroscopicity condition is 1.52 kPa.The parameters of α^d、n^d、θs^d、 Ks^d obtained under dehumidification condition are different from those obtained under hygroscopicity condition.The difference of these parameters determines the difference of hydo-mechanical interaction characteristics.The matrix suction and suction stress decrease with the increase of volume water content,while the permeability coefficient increases with the increase of volume water content.Under the same volume moisture content,the greater the dry density,the greater the matrix suction and the suction stress,and the smaller the permeability coefficient.