土工合成材料加筋土抗剪作用的试验研究

Shear characteristics of soil reinforced with geosynthetic material

本文通过4种用合成材料加筋的土体直剪试验,研究了加筋层数、筋材拉伸模量、土体压实度以及竖向压力等对加筋土体抗剪强度和应力-应变特性的影响。试验结果表明:加筋改变了土体的应力-应变特性,峰值抗剪强度增高,峰值后的残余强度较峰值强度的降低幅度减小,且达到峰值强度的剪切位移增大,土体延性提高。筋材拉伸模量过低时,加筋对土体的强度和应力-应变特性影响不大,加筋体的性质与素土接近。随加筋层数和筋材拉伸模量的增大,加筋体强度提高;竖向压力较低时,加筋体残余强度较其峰值强度提高幅度更明显,而竖向压力较高时,加筋体残余强度和峰值强度的提高幅度都相对较小;低压实度的加筋土体,峰值强度提高幅度相对较大,而高压实度的加筋土体,残余强度提高的幅度则较大。

The influences of geosynthetic material layer amount, tensile modulus, soil compactness and normal pressure on shear strength and stress-strain characteristics of reinforced soil are experimentally studied. Four kinds of geosynthetic material are to be used. The experimental result shows that the reinforcement improves the stress-strain behaviors of the soil. The peak shear strength of soil increases and the amount of reduction of residual strength decreases. As a result, the collapse of reinforced soil becomes more flexible and ductile. When the modulus of reinforcement is low, the stress-strain behaviors of the reinforced soil are almost the same as that of non-reinforced soil. With the increasing of the reinforcement modulus and layers, the influence of reinforcement on performance of reinforced soil becomes significant. Under low normal pressure the residual strength enhanced remarkably, while under high normal pressure both the peak and residual strength to be enhanced will not greatly. In case the compactness is relatively low the reinforcement will greatly enhance the peak strength, but if the compactness is high, the residual strength will be greatly elevated.