干湿循环作用下石膏岩劣化效应的试验研究

选取巴东十字垭隧道的石膏岩为研究对象,室内完成了0,1,3,6,12次干湿循环试验,测得了循环过程中吸水率、孔隙度和单轴压缩的试验数据。试验表明:石膏岩的吸水率和孔隙度与干湿循环次数呈对数函数形式,并随着干湿循环次数的增多而不断增大,但吸水率、孔隙度的增加量却逐渐减少;同样,石膏岩的单轴抗压强度和弹性模量随着干湿循环次数的增多而减小,并随着循环次数的增多,单轴抗压强度和弹性模量的减少量逐渐减少。通过分析对比石膏岩劣化参数变化率,得到干湿循环作用对石膏岩各个参数的劣化效果是不同的,其排序为:吸水率＞弹性模量＞单轴抗压强度＞孔隙度。

Laboratory Study on Degradation of Gypsum Rockwith Dry-Wet Cycles

Test data of water absorption rate, porosity and uniaxial compression of the gypsum rocks from Shiziya tunnel in Badong were obtained through 0, 1, 3, 6, 12 cycles of drying and wetting test.Results showed that the water absorption rate and porosity of gypsum rock were in logarithmic function relationship with the wet-dry cycles.With the increase of wet-dry cycle, water absorption rate and porosity both increased;but the increment alleviated.Meanwhile, the uniaxial compressive strength and elastic modulus both reduced with the number of wet-dry cycles;and the reduction decreased gradually.Furthermore, dry-wet cycles had biggest degradation effect on water absorption rate, followed by elastic modulus, uniaxial compressive strength, and porosity.