热应力作用下岩石拉张破裂数值模型研究

发布时间：2018-05-01 16:16

本文选题：岩石 + 热-固耦合　；参考：《西南科技大学》2017年硕士论文

【摘要】：温度变化会使岩石等脆性材料产生热应力,当热应力超过岩石自身的强度极限,就会使岩石产生破裂,这就是岩石热破裂现象。岩石热破裂会引起采矿工程安全问题。如在煤炭地下气化过程中,气化炉的炉壁围岩受到高温作用,使气化炉壁围岩范围内的应力场发生变化,导致围岩在热应力作用下发生破裂,严重时会形成冒顶。因此,开展岩石破裂的热-力耦合问题研究对采矿工程具有重要意义。本文基于拉张破坏理论,实现了拉张破坏有限元模型建立,并针对含软弱夹层边坡,考虑夹层埋深、倾角、厚度、边坡倾角4种因素对边坡破坏过程的影响,设定4种工况来进行边坡破坏过程数值模拟,分析了边坡在4种工况下坡体内裂纹扩展过程和第一主应力演变过程,为实际边坡工程防护提供参考。结合拉张破坏和热传导相关理论,建立了具有热-固耦合作用的热破裂数值模型,并利用存在解析解的厚壁圆筒算例验证该模型正确性。运用厚壁圆筒和内嵌颗粒计算模型,研究了岩石由温度梯度和热膨胀系数不同产生的热应力作用下破坏模式。模型计算结果与试验结果有较好的一致性,为分析岩石的热破坏过程和机制提供了一种新的有限元方法。
[Abstract]:The change of temperature will cause the thermal stress of brittle materials such as rock. When the thermal stress exceeds the strength limit of rock itself, it will cause the rock to break, which is the phenomenon of rock thermal fracture. Rock thermal rupture will cause safety problems in mining engineering. For example, in the process of underground coal gasification, the wall rock of gasifier is affected by high temperature, which changes the stress field in the surrounding rock of gasifier wall, resulting in the fracture of surrounding rock under the action of thermal stress, and the roof fall when serious. Therefore, the study of thermal-mechanical coupling of rock fracture is of great significance to mining engineering. Based on the tensioning failure theory, the finite element model of tensile failure is established in this paper. The influence of interlayer depth, dip angle, thickness and slope dip angle on slope failure process is considered for the slope with weak intercalation. The numerical simulation of slope failure process is carried out under four working conditions, and the process of crack propagation and the first principal stress evolution in slope under four conditions are analyzed, which provides a reference for practical slope engineering protection. Combined with the theory of tensile failure and heat conduction, a thermal fracture numerical model with thermal-solid coupling is established, and the validity of the model is verified by an example of thick wall cylinder with analytical solution. The failure mode of rock under the thermal stress caused by temperature gradient and coefficient of thermal expansion is studied by using the calculation model of thick wall cylinder and embedded particles. The model results are in good agreement with the experimental results, which provides a new finite element method for the analysis of the thermal failure process and mechanism of rock.
【学位授予单位】：西南科技大学
【学位级别】：硕士
【学位授予年份】：2017
【分类号】：TD311

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