砂土-混凝土接触面注浆剪切试验研究

Shear Experiment Study of Sand-Concrete Interface Considering Grouting

桩侧后注浆技术在桩基工程中被广泛应用,但关于桩土接触面注浆的剪切力学特性研究并不多见.利用改进后可界面注浆的大型多功能剪切仪进行了砂土与结构物接触面注浆情况下的剪切试验,研究了注浆对接触面力学特性的影响.试验结果表明,界面注浆呈压密注浆与劈裂注浆相伴随出现的形式,注浆显著提高了接触面的抗剪强度,接触面强度增大的幅度随着注浆量的增大而有减弱的趋势.在相同法向应力条件下,剪切应力-位移曲线未出现应变软化现象,表现出非线性关系.随着注浆量的增大,接触面的粘聚力随之增大,而摩擦角则随之减小.最后采用修正摩尔库伦模型对试验数据进行了拟合.本文所得结果对桩基工程桩侧后注浆的应用有一定的借鉴意义.

A series of sand-concrete structure interface shear tests considering the effect of different grouting volumes are performed by large direct shear apparatus;and the effect of grouting on mechanical characteristics of interface are studied.The experiment results show that the shear strength of sand-concrete interface is largely improved by the interfacial grouting;and the increasing magnitudes of shear strength decreased with the increasing of grouting volume.Under the condition of same normal stress,the relationship between the shear stress and the shear strain is nonlinear likely,without the occurence of strain softening.In addition,by using the curve fitting,it can be found that with the increase of grouting,the cohesion of interface increased and the friction angle decreased likely.At last,the modified Mohr-Coulomb model is used to fit the experiment data;and the related parameters are shown.The conclusion of this experiment is beneficial to the research of side-grouting pile engineering.