台阶开挖基岩-填方体界面剪切强度及变形特征研究

Study on Shear Strength and Deformation Characteristics of Stepped Excavation

以西南山区基础建设过程中高填方边坡工程为背景,为了研究含石率对基岩-填方体界面剪切特性与变形的影响,通过室内大型直剪试验,分别对两种含石率不同的试样进行直剪试验,分别研究填方体材料为纯土和在75%含石率的土石混合料条件下,结构面粗糙度、法向应力以及颗粒材料的微观力学特性对接触面剪切特性的影响。研究结果表明:含石率对填方体与基岩接触面的力学特性有显著影响,接触面剪切强度随含石率的增大明显提高;在相同条件下,含石率越小剪切过程的连续性越好;当含石率偏大且法向应力较高时,会对接触面前期的剪切强度形成不利影响。该研究成果可为填方体边坡设计、施工和工程的长期稳定性分析提供依据。

With the background of the high-fill slope project in the infrastructure construction of the southwest mountainous area,and with the aim to study the ef-fect of stone content on the shear characteristics and deformation of the bedrock-fill interface,large-scale direct shear tests were conducted on two types of speci-men with different stone contents to study the effects of structural surface roughness,normal stress and the micro-mechanical properties of the granular material on the shear properties of the contact surface under the condition that the filling material is pure soil and that the soil-rock mixture with 75%of stone content,respec-tively.The results showed that the stone content has a significant effect on the mechanical properties of the interface between the filling body and the bedrock,and the shear strength of the contact surface rises significantly with the increase of the rock content;Under the same conditions,the lesser the stone content,the better the continuity of the shearing process;When the stone content is relatively large and the normal stress is high,the shear strength of the front face of the contact will be adversely affected.The research results can provide a basis for the long-term stability analysis of the design,construction and engineering of the fill slope.