含充填岩石节理对应力波透反射特征影响的机制与规律研究

Because of the existing of joints, the wave propagation across a rock mass is very complicated. It is significant to understand the transmission and reflection mechanism caused by rock joints, which is an important topic in rock dynamics and has received considerable attention in geophysics, mining and underground construction. .In this regard, the split Hopkinson pressure bar (SHPB) tests will firstly be carried out for longitudinal- (P-) wave propagation across a filled joints in the present research. From the test recordings, the reflected and transmitted waves produced from the joint will be obtained. The mechanism for the effect the filled joints on wave propagation is then investigated. The parametrical study for the effects of the filling material, the thickness and the water content of the joints on wave reflection and transmission will also be studied. .In order to carry out the following theoretical study, we then want to know the dynamic model of the filled joints, which can be obtained from the test results for the stress vs closure curve of the filled joints..Thirdly, we will conduct the theoretial study to analyze the transmission and reflection mechanism caused by the filled rock joint. The stresses on the two sides of the filled joints can be observed from the test, from which the current displacement discontinuity method can be improved. According to the motion equation, the stresses and particle velocities before and after a filled joint are analyzed, so as to establish the interaction between the joint and stress waves. The wave propagation equation is derived and mathematically expressed. The wave propagation equation will include the effect of the joint thickness. The verification should be conduced by comparing the analytical calculations and the results from the tests. The mechanism for the effect the filled joints on wave propagation are then analyzed. The effects of the filling material, the thickness and the water content of the joints on wave reflection and transmission are systematically analyzed by using the theoretically method..From the above, the test results and theoretical analysis for the reflection and transmission mechanism caused by filled joints are of great significance to completely understand the complex process of stress wave propagation in jointed rock masses.

节理的存在使得应力波在岩体的传播过程中发生复杂的透反射现象，揭示含充填岩石节理对应力波透反射特征影响的机制与规律对于保障地震和爆破作用下岩体边坡和洞室的安全具有重要的意义。本项目首先应用霍普金森杆（SHPB）实验进行P波通过充填节理的透反射实验，研究输入杆和输出杆上的透射波和反射波，揭示影响应力波透反射特性的机制，并反映节理的充填材料、厚度和含水率对应力波透反射特性的影响。其次，根据实验结果分析应力波和节理的闭合量之间的关系，建立充填节理的动态法向力学模型。再次，通过分析两个节理面上的应力关系以及相对应的位移关系，建立考虑节理厚度效应的应力波传播方程，计算透反射应力波，并通过和实验的比较，验证理论分析的正确性。再此理论基础上分析节理对应力波透反射特性的影响机制，并研究充填节理的物理参数和应力波透反射规律的相关关系。研究成果对于深入理解应力波在节理处传播的复杂过程具有重要的意义。

节理的存在使得应力波在岩体的传播过程中发生复杂的透反射现象，揭示含充填岩石节理对应力波透反射特征影响的机制与规律对于保障地震和爆破作用下岩体边坡和洞室的安全具有重要的意义。本项目首先应用霍普金森杆（SHPB）实验进行P波通过充填节理的透反射实验，输入杆和输出杆上的透射波和反射波记录反映出应力波透反射规律，并反映节理的充填材料、厚度和含水率对应力波透反射特性的影响。研究结果表明：1）应力波通过任何充填节理都将出现幅值和频率的衰减；2）充填材料的种类对应力波的透反射产生不同的影响，当充填材料的含水量和节理的厚度相同时，应力波通过充填物为土的节理比通过充填物为沙的节理将产生更多的衰减；3）含水量对应力波的透反射产生不同的影响，对一同一种充填材料，含水量高的充填节理比含水量低的充填节理对应力波的衰减影响要明显；4）节理厚度应力波的透反射也产生不同的影响，对于同一种充填物且含水量相同时，节理越厚应力波的衰减越明显；5）根据实验数据可以得到作用在节理的法向应力和节理法向闭合量之间的关系，即节理的应力随着闭合量的增加而上升，且它们之间呈现非线性关系。当节理受到拉应力作用时节理张开，节理的应力几乎与闭合量无关而快速回落，反映出节理的压力学特性和拉力学特性的不同；6）基于实验结果提出充填节理的薄弱层界面模型，该模型反映了节理的充填种类、特性和节理厚度对应力波传播规律的影响以及对节理的动态法向力学特性的影响。7）节理不同拉压动态力学特性对应力波透反射规律具有不同的影响。. 实验结果主要针对人工充填节理开展了系列的实验和理论研究。经费还留了20余万，计划开展天然节理对应力波透反射规律的影响。