干湿循环条件下水泥改良红砂岩土的力学特性试验研究

为研究水泥改良红砂岩土受到干湿循环作用各项力学性质的变化规律,将未改良与掺入不同水泥剂量的红砂岩土试件进行干湿循环,并开展室内三轴试验,研究干湿循环后土体应力-应变曲线、破坏面形式、峰值强度、弹性模量的变化规律。研究结果表明:水泥作为改良剂不改变红砂岩土的应力-应变曲线,但在曲线的各个阶段,水泥对红砂岩土的受力特征均有一定改善;水泥使红砂岩土的破坏形式由塑性破坏向脆性破坏转变;掺入不同剂量的水泥,红砂岩土的峰值强度和弹性模量均有明显提高。随着干湿循环次数的增加,经水泥改良的试件弹性模量和峰值强度呈先降低后提高的趋势;采用指数函数关系式对弹性模量和峰值强度进行多元非线性拟合,建立弹性模量和峰值强度关于干湿循环次数、围压与水泥剂量的关系式,拟合效果理想。

Experimental Study on Mechanical Properties of Cement-modified Red Dandstone Soil under Dry-wet Cycle

In order to study the changes of mechanical properties of cement-modified red sandstone soil subjected to dry-wet cycle, the red sandstone soil specimens with different cement dosages were not modified and subjected to dry-wet cycle, and then the indoor triaxial test was carried out to study the wet and dry After the cycle, the stress-strain curve, the failure surface form, the peak strength and the elastic modulus of the soil are changed, and the multivariate relationship between the peak strength and the elastic modulus is calculated by software. The results show that cement as a modifier does not change the stress-strain curve shape of red sandstone soil, but at each stage of the curve, the stress characteristics of cement on red sandstone soil are improved. The damage form of red sandstone soil by cement is The plastic failure changes to brittle failure; the peak strength and elastic modulus of the red sandstone soil are significantly improved by incorporating different doses of cement. With the increase of the number of dry and wet cycles, the elastic modulus and peak strength of the cement-modified specimens first decreased and then increased. The exponential function relationship was used to perform multivariate nonlinear fitting on the elastic modulus and peak strength to establish elasticity. Modulus and peak strength The relationship between the number of dry and wet cycles, confining pressure and cement dosage is ideal.