红层软岩崩解演化规律与强度弱化试验研究

Experimental Study on the Evolution Law of Red Layer Soft Rock Disintegration and Strength Weakening

红层软岩遇水会形成裂隙,造成岩体剥落、崩解,导致其强度降低,从而影响边坡的整体稳定性.为了探究降雨条件下红层软岩的崩解演化规律和强度弱化特性,采用干湿循环和单轴压缩试验,对软岩的崩解现象、崩解机理以及力学性能进行了分析研究,结果表明:泥岩的颗粒级配会随循环次数的增加而改变;泥岩的耐久性受干湿循环作用的影响很大;随着干湿循环次数递增,软岩的峰值强度和弹性模量逐渐下降,泊松比则呈上升趋势;红层软岩的崩解过程为:原生层面存在-水分浸润岩体-新裂隙产生以及原生层面扩展-干湿循环作用-岩体经历弱崩解、中崩解、强崩解阶段-丧失整体性,最终成为散体.干湿循环对软岩造成的劣化损伤作用具有累积性和不可逆性,且前期劣化效果更为显著.蓬莱镇组红层软岩在成分、结构、构造等方面与其它地区红层不同,导致了崩解的差异性.研究可为红层软岩地区因降雨引起的岩体强度损失折减程度进行判定.

When the red soft rock encounters water,it will form cracks,causing the rock mass to peel and disintegrate,resulting in decrease of its strength,thus affecting the overall stability of the slope.In order to explore the disintegration evolution law and strength weakening characteristics of red-layer soft rock under rainfall conditions,the disintegration phenomenon,disintegration mechanism and mechanical properties of soft rock were analyzed and studied by drying-wetting cycle test and uniaxial compression test.The results show that the particle gradation of mudstone will change with the increase of the number of cycles.The durability of mudstone is greatly affected by the dry and wet cycle.With the increase in the number of dry and wet cycles,the peak strength and elastic modulus of the soft rock gradually decrease,and the Poisson ratio is on the rise.The disintegration process of the red layer soft rock is in the following stage,i.e.the existence of the primary level-the water-infiltrated rock mass-the generation of new cracks and the expansion of the primary level-dry and wet cycle-the rock mass in weak disintegration,medium disintegration and strong disintegration-fully disintegration.The effect of dry and wet cycle on the deterioration damage caused by soft rock is cumulative and irreversible,and the early deterioration effect is more significant.The red layer soft rock in Penglai Town Group is different from the red layer in other regions in terms of composition,texture and geological structure,which leads to the difference of disintegration.The study can determine the degree of reduction of rock mass strength loss caused by rainfall in the red layer soft rock area.