扰动荷载下含裂隙硬岩的蠕变行为研究

发布时间：2018-03-23 16:37

本文选题：蠕变扰动试验　切入点：含孔洞大理岩　出处：《湖南工业大学》2017年硕士论文

【摘要】：洞室开挖过程中,开挖扰动如应力释放转移和爆破等荷载造成围岩损伤,其长期稳定性将是关注的问题。结合某金属矿山三步骤回采,为分析其隔离矿壁在多次扰动作用下长期稳定性,分析了某典型矿岩-大理岩,分析了含单一孔洞条件下的蠕变扰动特性。1、采用SHPB冲击试验系统对含不同直径孔洞的大理岩进行了单轴压缩下的扰动蠕变试验。以不同孔径的大理岩为研究对象,采用分级加载方式,并在蠕变一段时间后施加冲击荷载,进行了含不同孔径的大理岩单在轴条件下的扰动蠕变压缩试验。发现孔洞大理岩的孔径不同,大理岩的长期强度也发生改变;采用不同的冲击荷载大小对含相同孔洞大小的大理岩进行了单轴压缩扰动蠕变试验,发现扰动荷载越大,岩石破坏时的荷载越小,即扰动荷载的大小岩石蠕变特性的影响很大。2、根据扰动荷载下含孔洞大理岩的蠕变曲线特征,对含孔洞大理岩在蠕变模型本中需要的基本元件及其组合方式进行了辨识分析,引入了能描述瞬时弹性变形、衰减蠕变变形、等速蠕变变形形式的Burgers模型;在MATLAB中采用最小二乘法,根据Burgers模型本构方程对D-6孔洞大理岩的蠕变试验曲线及施加扰动后改变Burgers模型中Kelvin体中的两个参数进行了拟合,获得了D-6孔洞大理岩在各级荷载下及每次扰动前后的蠕变参数。试验曲线和理论曲线具有很好的相似性,说明用Burgers模型及改变Kelvin体中的参数来描述孔洞大理岩的扰动蠕变特性具有一定的可信度。3、依据室内扰动蠕变试验结果,对含8mm孔径的大理岩进行了数值模拟,在静载蠕变模块的基础上引进了动力计算模块。单轴压缩扰动蠕变模拟曲线与室内试验曲线相比较,二者具有较好的一致性。
[Abstract]:During the excavation of a cavern, the disturbance of excavation, such as stress release, transfer and blasting, will cause damage to surrounding rock, and its long-term stability will be a problem of concern. In order to analyze the long-term stability of the isolated ore wall under the action of multiple disturbances, a typical ore rock-marble is analyzed. In this paper, the creep disturbance characteristics of marble with single pore are analyzed. The creep tests of marble with different diameter holes under uniaxial compression are carried out by using SHPB impact test system. The marble with different pore sizes is taken as the object of study. The creep compression tests of marble with different pore sizes under axial condition were carried out by means of step loading and shock loading after creep for a period of time. It was found that the pore size of porous marble was different. The long-term strength of marble is also changed. Uniaxial compression creep tests of marble with the same pore size are carried out with different impact loads. It is found that the larger the disturbance load is, the smaller the load is when the rock is destroyed. According to the creep curve characteristics of porous marble under disturbed load, the basic components and their combinations in creep model of porous marble are identified and analyzed. The Burgers model which can describe instantaneous elastic deformation, attenuated creep deformation and constant velocity creep deformation is introduced, and the least square method is used in MATLAB. According to the constitutive equation of Burgers model, the creep test curve of D-6 hole marble and two parameters of Kelvin in Burgers model are fitted after disturbance. The creep parameters of D-6 hole marble under various loads and before and after each disturbance are obtained. The experimental and theoretical curves are very similar. It is shown that the Burgers model and the parameters in the Kelvin body can be used to describe the perturbed creep characteristics of porous marble. According to the results of indoor disturbed creep tests, the numerical simulation of marble with 8mm pore size is carried out. The dynamic calculation module is introduced on the basis of static load creep module, and the simulation curve of disturbance creep under uniaxial compression is in good agreement with that of laboratory test.
【学位授予单位】：湖南工业大学
【学位级别】：硕士
【学位授予年份】：2017
【分类号】：TU45

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