相似材料单轴压缩力学性能及强度误差来源分析

Mechanical properties of similar material under uniaxial compression and the strength error sources

为提高相似材料模型试验的模拟精度,通过单轴压缩测试了2种不同材料(砂-石膏、砂-水泥-石膏)、不同配比试件的应力-应变特性,分析其力学性能、破坏特征,并探讨了相似材料模型制作及试件测试过程中的误差来源。研究结果表明:1)2种相似材料试件在加载过程中均能表现出良好的弹塑性性质,可针对不同试验岩体进行模拟仿真;2)2种相似材料试件峰后软化段平稳,残余强度稳定;3)由于相似材料体胶结不够充分,原发损伤多,加载过程中易出现异常卸压和应力波动,破坏特征主要以张裂和共轭双剪为主;4)相似材料模型制作过程中,人为因素影响较大,提出了配制和测试过程中的误差来源,应尽量避免以增加相似材料试验精度。

In this paper, in order to improve the accuracy of similar simulation experiment, we tested the stress-strain behaviors of similar material specimens with different compositions （sand-plaster, sand- cement-plaster） and proportions by uniaxial compression testing, analyzed the mechanical properties and post-peak failure characteristics, and investigated the error sources during the production of similar material models and testing of specimens. The results show that： 1） The two similar materials both show good elastic-plastic properties in the loading process, thus, they can be used to simulate different rock mass; 2） The post-peak strain-softening processes of the two materials are smooth, and the residual strengths are stable; 3） Due to the insufficient cementation and primary damage of the similar materials, abnormal pressure-relief and stress fluctuations are prone to appear in the loading process, and the main failure modes are the tensile failures and conjugate shear fracturings; 4） Human factors affect a lot dur- ing the production procedures of similar material models, thus, in order to increase the accuracy of similar material experiment, we put forward the error sources in the preparation and test processes and try to avoid them.