泥皮对花岗岩残积土与结构接触面力学特性影响的试验研究

摘要

Bored piles are widely used in railway bridges.Residual slurry is unavoidable during the construction of piles.A series of tests were carried out by using a direct shear apparatus to study mechanical behavior of the interface between granite residual soil with slurry and concrete plate.The effects of thickness and water content of slurry were analyzed in this paper.The results show that with the increase of the thickness of slurry,the interface shear strength decreases,and so is the dilatancy of the interface soil.The normal stress is larger,the greater the amplitude of interface shear strength decreases.The friction is the major component of interface shear force without slurry,while the cohesion is the major component of that with slurry.With the decrease of the dilatancy of the interface soil,the water content and normal stress increase.The water content imposes greater influence on the friction angle than on the cohesion.%钻孔灌注桩在铁路桥梁中被广泛采用,但施工中残留泥皮难以避免.利用土工直剪仪对夹有泥皮的花岗岩残积土与混凝土板接触面的力学特性进行试验研究,分析泥皮厚度和含水率对接触面抗剪特性的影响.结果表明:随着泥皮厚度的增大,接触面的抗剪强度下降,接触面土体的剪胀性降低;法向应力越大,接触面抗剪强度降低的幅度越大;泥皮不存在时,接触面的抗剪以摩擦为主,而泥皮存在时,接触面的抗剪作用力以黏聚力为主;增大泥皮含水率和增大法向应力均会导致接触面土体的剪胀性降低,含水率对接触面摩擦角的影响大于对黏聚力的影响.