黑方台古风化红层砂泥岩物理性质试验研究

Experimental Study on Physical Properties of Palaeo-Weathering Red Sandy Mudstone in Heifangtai Area

以黑方台地区白垩纪古风化红层砂泥岩为对象,选择典型剖面进行室内试验和现场回弹试验,获得了砂泥岩基本物理性质参数和回弹试验强度值,对其工程地质性质进行了综合评价,探讨了红层砂泥岩的古风化作用及其对滑坡发育的影响。结果表明:剖面上随着红层风化程度的提高,岩石颗粒密度增大,干密度降低,总孔隙率增大,吸水性减弱,纵波波速降低,岩石回弹值下降,岩石强度明显降低;在黑方台地区虽然导致滑坡发生的直接诱发因素为灌溉,但是基岩表层的软弱带(古风化壳)往往构成黄土滑坡的底界,是黄土滑坡形成的控制性边界条件,是导致区内滑坡频繁发生的基本控制因素。

Taking the cretaceous paleo-weathering red sandy mudstone as research object, this study achieved the basic physical propertyparameters and rebound strength values of sandy-mudstone by conducting laboratory test and field rebound test on the selected typical profiles.It comprehensively evaluated the engineering geological properties and discussed the influence of the paleo-weathering effect on thedevelopment of landslide. The results show that with the deepening of paleo-weathering, dry density, hygroscopicity, velocity of longitudinalwave, rebound value and strength of rock decrease, while particle density and total porosity increase. Though the direct intriguing factor oflandslide in Heifanftai area is irrigation, the paleo-weathering crust on the rock surface of bottom occurrence of landslides in this area for itoften forms the loess landslide which is the controlling boundary condition of loess landslide.