【作者】 梁玉雷；

【导师】 冯夏庭；

【作者基本信息】 中国科学院研究生院（武汉岩土力学研究所） ， 岩土工程， 2009， 硕士

【摘要】 随着西部大开发的进行,岩土工程所处的环境日益复杂,使得岩体的性质发生了很大的变化,工程灾害也日益增多。温度周期变化(季节)带来的大温差,会使岩体产生温度应力和时效变形,造成岩体裂隙的周期性扩张与收缩。针对上述问题本文开展了一系列温度周期变化与渗透压力作用下大理岩蠕变试验,获得了温度周期变化和渗透压力作用下大理岩时效变形规律;建立了温度周期变化和渗透压力作用下大理岩热黏弹塑性蠕变模型;并将所建立的热黏弹塑性本构方程引入温度-水-应力(THM)三场耦合理论中,采用有限元方法模拟了温度周期变化与渗透压力作用下大理岩的蠕变行为。主要研究工作及获得的有益认识如下:1、通过大理岩在不同温度、水压、轴压和围压条件下的三轴蠕变试验,分析了大理岩在不同温度、水压、轴压和围压下轴向变形随时间的变化规律,研究了温度周期变化和渗透压力作用下大理岩蠕变的变形机制,掌握了温度周期变化和渗透压力作用对大理岩三轴蠕变影响的基本规律。试验表明:90℃恒温条件下比30℃恒温条件下大理岩的蠕变变形量和瞬时弹性变形量均减少,同时蠕变变形量和瞬时弹性变形量的比值也减少,30℃至90℃温度周期变化作用下,大理岩轴向蠕变变形随温度周期变化次数的增加呈阶梯状增加,说明温度周期变化造成大理岩的损伤,孔隙水压力的存在使岩石的蠕变变形量与瞬时弹性变形量的比值增大,提高了温度周期变化造成大理岩的损伤影响,而围压的增加使岩石的蠕变变形量与瞬时弹性变形量的比值明显减小,同时对温度周期变化造成大理岩的损伤量增大。2、在三轴蠕变试验规律的基础上,把热弹性元件及温度周期变化损伤因子引入西原体模型,建立了温度周期变化和渗透压力作用下大理岩热黏弹塑性蠕变模型。模型与试验相吻合,较好地反映了温度周期变化和渗透压力对大理岩蠕变的影响。3、将建立的大理岩热黏弹塑性蠕变本构方程引入THM三场耦合理论,建立了考虑温度周期变化THM三场耦合控制方程组,利用伽辽金法(Galerkin)得到了考虑温度周期变化THM三场耦合控制方程组的等价弱形式,获得了考虑温度周期变化THM三场耦合控制方程组的有限元计算公式。运用Visual Fortran编制了考虑温度周期变化THM三场耦合蠕变的有限元计算程序,模拟再现了温度周期变化和渗透压力作用下大理岩蠕变行为的影响。更多还原

【Abstract】 With the construction of the western development, the environment of geotechnical engineering is more and more complex, which results in great changes of mechanic properties of the surrounding rockmass and increasing engineering disasters. Large temperature difference by cyclic temperature (annual) makes rockmass generate thermal stress and time-dependent deformation, which results in the periodic expansion and contraction of rock fracture. Aiming at these problems above, a set of creep experiments on marble under cyclic temperature as well as permeable pressure are carried out; the law of time-dependent deformation of marble under cyclic temperature and permeable pressure is mastered; thermo-visco-elastic-plastic creep model of marble under cyclic temperature and permeable pressure is proposed, which is introduced the coupled thermo-hydro-mechanical (THM) theory. Concretely, creep behaviors of marble under cyclic temperature and permeable pressure are simulated by finite element method. In sum, the main work and conclusions including:1. The triaxial creep experiment of marble under different temperature, pore water pressure, axial pressure and confined pressure are carried out, and the variation law of time-dependent axial deformation of marble under different temperature, pore water pressure, axial pressure and confined pressure is analyzed, the creep deformation mechanism of marble under cyclic temperature and permeable pressure is investigated, and the basic laws of effects on triaxial creep of marble by cyclic temperature and permeable pressure are mastered. The experimental results indicate that: the ratio of creep deformation of marble to instantaneous elastic deformation under 90℃constant temperature condition is less than 30℃constant temperature condition, the axial creep deformation of marble increases ladderlikely with the numbers of the cyclic temperature, which suggests that the cyclic temperature makes marble mass damage. Because of the exist of pore water pressure, the ratio of creep deformation of marble to instantaneous elastic deformation is bigger, however, the damage of cyclic temperature to marble is not significantly effected. Because of the increasing of confined pressure, the ratio of creep deformation to instantaneous elastic deformation decreases significantly, but the damage of cyclic temperature to marble increases.2. Base on the law of triaxial creep experiments, the thermo-elastic component and factor of damage caused by cyclic temperature is induced to k-b model, thermo-visco-elastic-plastic creep model of marble under cyclic temperature and permeable pressure is proposed, which is suitable to the experiments, properly reflects the effect of cyclic temperature and permeable pressure to marble creep.3. thermo-visco-elastic-plastic creep model of marble which is proposed above is induced to coupled THM theory, so the coupled THM governing equations about cyclic temperature are proposed, the equivalent weak forms of coupled THM governing equations considing cyclic temperature are obtained by Galerkin method, as well as the calculation formulas of finite element method. Then the calculation program of coupled THM creep about cyclic temperature written in Visual Fortran is developed, the creep progress of marble under cyclic temperature and permeable pressure is simulated. The influence of cyclic temperature and permeable pressure on marble are analyzed.更多还原