岩石节理全剪切-渗流耦合试验技术和系统研制

The mechanical and hydraulic properties of rockmasses are mainly predomintated by that of joints included in rock masses. As the mechanical and hydraulic properties of joints interact with each other, especially during shear process, the coupled shear-flow properties of joint under high hydraulic pressures become key problems in rock mechanics and rock engineering. The coupled shear-flow test apparatus is an important means to investigate these problems. Although flow tests for joints under normal stresses or after some shear displacements with low hydraulic pressures were performed extensively and a lot of novel results were obtained, due to absence of special shear box for flow test during shearing, few researches and flow tests under high hydraulic pressures are conducted during post-peak shear process. Therefore, in this project, emphases will be placed on key technologies, such as sealing system of shear box under high hydraulic pressures, measurements and controls of high pressure and small flux and constant stifness control, to develop a new coupled shear-flow test apparatus for rock joints,which will provide equipment and technology supports for sovling rock mechanics problems in rock masses engineerings such as layway, tunnels, underground caverns, slopes and so on.

节理的力学和渗流性质对岩体的力学和渗流性质起着支配作用，节理的力学和渗流性质存在相互的耦合作用，尤其是在剪切过程中，因此，高渗透压力作用下节理的剪切-渗流耦合性质是岩体力学和工程中迫切需要解决的关键科学问题，而岩石节理全剪切-渗流耦合试验系统是揭示这一科学问题的重要手段。虽然已有节理在不同法向应力下的渗流试验以及较低渗流压力下节理剪切位移后的渗流试验的研究成果，但是较高渗流压力下在节理剪切达到其峰值后的过程中进行的渗流试验和研究还是空白，主要是由于一直没有能在节理剪切过程中进行渗流试验的渗流剪切盒。本项目拟重点攻克高渗流压力下渗流剪切盒在剪切过程中的密封、高渗流压力和小流量的测量和控制、常刚度控制等技术关键，研制岩石节理全剪切-渗流耦合试验系统及相应的试验技术，为研究巷道、隧道、地下洞室、边坡等岩体工程中的科学问题提供仪器和技术支撑。

近年来随着核废料处理、天然气及CO2地下储存、压气储能、水利和采矿工程等大型深部地下岩体工程的兴建，高渗透压力作用下节理岩体的力学和渗流及其耦合特性是关系该类地下工程安全与否的关键因素。由于节理剪切-渗流耦合试验系统要实现高渗透压力（3MPa）条件下边剪切边渗流的过程，保证试验系统中剪切盒的密封性成为试验系统成功的技术瓶颈。本项目在国外同类型仪器研究的基础上，自主发展和研制全新的节理剪切渗流试验系统，系统主要包括部分：（1）剪切渗流盒及其密封系统；（2）渗流伺服控制系统；（3）主机和加载系统；（4）高精度测量和多通道伺服加载控制系统和（5）试验操作软件系统。据此，本系统精确地实现了在法向和剪切向多种加载边界条件的加载方式和控制问题，尤其实现了常法向刚度边界条件以及法向流变-渗流、剪切流变-渗流的加载方式，攻克了高渗透压和小流量的测量和控制技术，并解决了在3MPa渗透压力下，在节理剪切过程中上、下剪切盒具有法向和剪切位移（最大剪切位移20mm，即试件长度的10%）动态情况下岩石节理密封的关键技术难题，并初步应用于深部岩体工程中的节理剪切-渗流、剪切流变-渗流的试验研究。该试验装备是国内外首台能达到3MPa渗透压力的岩石节理剪切渗流仪器，填补了在较高渗透压力下岩石节理剪切达到峰值后直至残余强度整个过程中渗流试验和研究的空白。仪器的成功研制，将使我国在岩石节理水力学性质研究技术水平、方法和仪器达到国际领先水平，对促进我国节理力学和水力学特性基础前沿研究起到积极推动作用。