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投稿时间：2021-12-01 修订日期：2022-01-19
投稿时间：2021-12-01 修订日期：2022-01-19
中文摘要: 随着中国能源资源开采逐步向深部转移，采用浅部参数研究深部问题、采用静态参数研究动态问题会造成工程设计时的科学依据不足。由于黏土的初始应力状态对其动力学性质有显著影响，本文采用长时、分级、高压固结方式模拟黏土的原始应力赋存环境；采用分离式霍普金森杆（SHPB）试验装置对侧限条件下的高压固结黏土进行峰值应变率范围为200～800 s–1的冲击压缩试验，分析了黏土应力记忆效应、应变率效应和动态压缩过程。结果表明：黏土的应力历史影响了其动态压缩过程，试样依次经历压实段、线弹性加载段、线性卸载段；在动载下，黏土压实段与线弹性加载段应力拐点的均值为3.8 MPa，与先期固结应力4.2 MPa具有相关性，且压实段应变均值约为试样破坏应变的33%。采用200和300 mm的短子弹进行冲击加载时，黏土试样未发生稳定的塑性变形；分析应力–应变率曲线发现，黏土的压实过程吸收了一部分动载能量，使其无法持续进行动态压缩行为，但进入动态压缩阶段后黏土受子弹长度影响较小；黏土试样动态加卸载段模量随应变率同步增加，但加卸载模量的比值稳定在0.45左右，表明更高的冲击速度没有造成试样进一步损伤，这与冲击后的宏观破坏现象及塑性变形分析相互印证。针对软弱、松散颗粒体材料，高压固结方式为研究其动力学性质提供了一种思路。
Abstract:With the gradual transfer of energy resources mining from shallow to deep in China, the current situation of using shallow parameters to solve deep problems and static parameters to solve dynamic problems results in the lack of scientific basis in engineering design. The initial stress state of clay has a significant influence on its dynamic properties. The long-term, graded, high-pressure consolidation method was utilized to simulate the original stress environment of clay, and the SHPB experimental device was employed to perform impact compression on the high-pressure consolidated clay under lateral restriction conditions with a strain rate ranging from 200 to 800 s–1. The stress memory effect, strain rate effect, and dynamic compression process of clay were studied. The experimental results show that the stress history of clay affects its dynamic compression process. The sample goes through the compaction section-linear elastic loading section-linear unloading section in turn. The average stress of switching point between the compaction section and linear elastic loading section under dynamic load is 3.8 MPa, which is correlated with the pre-consolidation stress of 4.2 MPa; the strain of compaction section is about 33% of the soil failure strain as well. The soil exhibits an elastic loading and linear unloading section without being a stable plastic section under the experimental strain rate, as the bullet is 200 mm or 300 mm long. It is found from the stress–strain rate relationship that the compaction section absorbs lots of the compaction energy, resulting in an unstable plastic deformation or even sudden unloading in the soil sample. The modulus of the loading and unloading section increases simultaneously with the strain rate, but the ratio of the two remains stable, which means higher impact velocity does not lead to far more damage. It can also be seen from the phenomenon of damage after impaction as well as the plastic flow analysis. At last, the high-pressure consolidation method provides an approach to studying the dynamic properties of weak and loose granular materials.
keywords: soil dynamics SHPB dynamic mechanical property lateral restriction condition high consolidation stress initial stress state
文章编号：202101189 中图分类号：TU43 文献标志码：
基金项目:国家自然科学基金项目（51934001；51774287）；国家重点研发计划项目（2016YFC0600903）；矿山灾害预防控制教育部重点实验室开放基金（JMDPC202103）
作者简介:第一作者：陈骏陈 骏（1990—），男，副研究员. 研究方向：岩土工程；矿井建设. E-mail：cj0354@cumtb.edu.cn
引用文本：
陈骏,张祥,赵康朴,易辉,杨仁树.初始应力状态对侧限条件黏土动态压缩过程和力学性能的影响[J].工程科学与技术,2023,55(3):69-76.
CHEN Jun,ZHANG Xiang,ZHAO Kangpu,YI Hui,YANG Renshu.Effect of Initial Stress State on Dynamic Compression Process and Mechanical Properties of Clay Under Lateral Restriction Conditions[J].Advanced Engineering Sciences,2023,55(3):69-76.
引用文本：
陈骏,张祥,赵康朴,易辉,杨仁树.初始应力状态对侧限条件黏土动态压缩过程和力学性能的影响[J].工程科学与技术,2023,55(3):69-76.
CHEN Jun,ZHANG Xiang,ZHAO Kangpu,YI Hui,YANG Renshu.Effect of Initial Stress State on Dynamic Compression Process and Mechanical Properties of Clay Under Lateral Restriction Conditions[J].Advanced Engineering Sciences,2023,55(3):69-76.