不同先期固结压力下的错动带力学特性研究

发布时间：2018-02-07 16:54

本文关键词： 错动带先期固结压力颗粒破碎　出处：《岩土力学》2017年01期 　论文类型：期刊论文

【摘要】：针对白鹤滩大型水电站揭露的错动带,探索了一种反映原岩应力状态的错动带试样制备方法,采用替代法对错动带进行超粒径处理,同时控制先期固结压力和稳压时间进行静载固结,并基于不同先期固结压力、不同高围压下的不固结、不排水三轴试验,结合矿物成分分析试验和扫描电镜试验,分析了不同先期固结压力下错动带的力学和变形特性。试验结果表明,不同高围压、不同固结压力下错动带应力-应变关系曲线基本表现为有剪胀行为的应变硬化型力学行为,且多为腰鼓型塑性破坏;在相同固结压力条件下,随着围压升高,错动带试样破坏应力、变形模量和泊松比均呈增大趋势,扩容效应更明显;相同围压条件下,随着先期固结压力的增大,错动带破坏应力逐步提高,弹性模量逐渐增大,而泊松比略有减小,敏感性不大;同时黏聚力和内摩擦角随固结压力的增加而分别减小和增大,呈劣化趋势。错动带微观结构的定性和定量分析进一步揭示了错动带作为一种夹杂错动后残留有岩石碎屑(块)软弱物质的颗粒类材料,在高应力下其塑性变形主要来源于颗粒破碎和颗粒的定向排列。因此,先期固结压力是影响错动带性质的重要因素。
[Abstract]:In view of the dislocation zone exposed by Baihetan large hydropower station, a method of preparing the specimen reflecting the stress state of the original rock is explored, and the superparticle size of the fault zone is treated by the substitution method. At the same time, the pre-consolidation pressure and steady pressure time are controlled for static consolidation. Based on the unconsolidated and undrained triaxial tests under different pre-consolidation pressures and high confining pressures, combined with mineral composition analysis tests and scanning electron microscopy tests, The mechanical and deformation characteristics of the staggered zone under different preconsolidation pressures are analyzed. The experimental results show that the stress-strain relationship curve of the staggered zone under different high confining pressures and different consolidation pressures is basically a strain-hardening mechanical behavior with shear expansion behavior. Under the same consolidation pressure, with the increase of confining pressure, the failure stress, deformation modulus and Poisson's ratio of the specimen in the staggered zone are all increasing, and the expansion effect is more obvious under the same confining pressure. With the increase of preconsolidation pressure, the failure stress and elastic modulus of the dislocation zone increase gradually, while the Poisson's ratio decreases slightly, and the cohesion force and the internal friction angle decrease and increase with the increase of the consolidation pressure, respectively. The qualitative and quantitative analysis of the microstructure of the fault zone further reveals that the fault zone is a kind of granular material with residual rock debris (block) after the inclusion of the fault zone. The plastic deformation under high stress mainly comes from the particle breakage and the directional arrangement of particles. Therefore, the preconsolidation pressure is an important factor affecting the properties of the dislocation zone.
【作者单位】：中国科学院武汉岩土力学研究所岩土力学与工程国家重点试验室;东北大学深部金属矿山安全开采研究中心;
【基金】：国家自然科学基金国际合作重大项目(No.41320104005);国家自然科学基金重点项目(No.11232024);国家自然科学青年基金(No.51309219)~~
【分类号】：TU45

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