Experimental Study on Shear Strength of Gravel Silty Clay from a Post-Earthquake High Slope

Based on direct shear tests of gravel silty clay from the high slope of Daju Mountain in Niufei Village, Pingtong Town, Sichuan Province after the 5.12 Wenchuan Earthquake, change laws of shear strength under different water content, dry density and maximal grain-diameter were studied. Through analyzing variation curves on shear strength and two indexes, cohesion C and angle of internal friction , conclusions can be drawn that shear strength goes down along with the growth of water content, goes up along with the growth of dry density, and is sensitive to the change of maximal grain-diameter; the influence of water content on shear strength and the two indexes, is largest, dry density larger and maximal grain-diameter worst. And the change mechanism of shear strength was interpreted rationally. Simultaneously the powerful functions were used to fit the relationships between shear strength indexes and the three influencing factors respectively. The paper accumulates basic data for shear strength study of the post-earthquake soil and provides important references for safety evaluation of the post-earthquake high slopes under harmful conditions, for example heavy rain and so on.