聚丙烯纤维增强橡胶砂固结不排水剪切试验

Consolidated Undrained Shear Test of Polypropylene Fiber Reinforced Rubber Sand

鉴于橡胶砂作为回填材料时承载力低和变形量大的问题,采用加入聚丙烯纤维(PPF)的方法提高橡胶砂的力学性能,提出了聚丙烯纤维增强橡胶砂的半干拌式制备方法,通过48组聚丙烯纤维增强橡胶砂、普通橡胶砂和纯砂试样的固结不排水剪切试验,探究了聚丙烯纤维掺量和橡胶掺量等参数对聚丙烯纤维增强橡胶砂主要力学变形特征参数的影响.结果表明:聚丙烯纤维对橡胶砂弹性模量的影响较小;聚丙烯纤维增强橡胶砂具有先剪缩后剪胀破坏的特征,其偏应力与轴向应变关系为应变硬化型;聚丙烯纤维可有效提高橡胶砂的内摩擦角和黏聚力;聚丙烯纤维增强橡胶砂破坏偏应力的提升效果十分显著,最高可提高3倍.

Considering the low bearing capacity and large deformation of rubber sand as backfill material,a method involving the addition of polypropylene fibers(PPF)to rubber sand was employed to enhance its mechanical performance.A semi-dry mixing method for preparing polypropylene PPF reinforced rubber sand was proposed.Through 48 sets of consolidated undrained shear tests on PPF reinforced rubber sand,ordinary rubber sand,and pure sand samples,the influence of parameters such as PPF content and rubber content on the main mechanical deformation characteristics of PPF reinforced rubber sand was investigated.The results indicate that PPF fibers have a relatively small impact on the elastic modulus of rubber sand.PPF reinforced rubber sand exhibits a characteristic failure pattern of initial shear contraction followed by shear dilation,with a strain-hardening relationship between shear stress and axial strain.PPF fibers effectively enhance the internal friction angle and cohesion of rubber sand.The improvement in the failure shear stress of PPF reinforced rubber sand is significant with a maximum increase of up to three times.