可溶岩裂隙溶蚀-损伤耦合演化特征及岩溶隧道围岩失稳致灾机制研究

Aiming at safety of surrounding rock during the operation of Karst tunnel which combined with the stability of surrounding rock and long-term reliability of supporting structure, the system research on this project has been done. At first, through a series of tests such as meso-mechanics test, triaxial compression test, creep test, coupled mechanics-penetration-dissolution test of Karst rock cracks, Karst rock damage characteristics test with dissolving effect and bolt long-term reliability simulation test with dissolving effect, meso-destruction mechanism and macro-mechanical characteristics of Karst rock, coupled dissolved-damage characteristics of Karst rock cracks, the quantitative relationship between macro-dissolving speed and damage characteristics, and the machanism and weaken law of bolt long-term reliability with dissolving effect have been obtained. Based on the result of Karst rock mechanical test and coupled mechanics-penetration-dissolution test of Karst rock cracks, damage model of Karst rock crack with dissolving effect has been built. And then, based on coupled dissolved-damage characteristics of Karst rock cracks and the machanism of bolt long-term reliability with dissolving effect, mechanism of instability of surrounding rock of Karst tunnel has been obtained. At last, associated with mechanism of instability of surrounding rock of Karst tunnel and damage model of Karst rock crack with dissolving effect and the quantitative relationship between macro-dissolving speed and damage characteristics and the weaken law of bolt long-term reliability with dissolving effect, combined qualitative and quantitative method for the forecast on long-term safety trend of surrounding rock with the influence for bolt long-term reliability by dissolving effect during the operation of Karst tunnel has been obtained and applied into the actual tunnel engineering. The achieved results can provide the important theoretical and technical support for design and construction and safe operation of tunnel engineering in Karst area of China.

本项目以岩溶隧道运营期间围岩安全性（围岩自身稳定性和支护结构长期可靠性共同作用结果）为研究目标开展系统研究，首先通过一系列试验，揭示可溶岩细观破坏机制和宏观力学特征、可溶岩裂隙溶蚀－损伤耦合演化特征、可溶岩宏观溶解速度与其损伤特性之间的定量关系、岩溶作用下锚杆长期可靠性弱化机制与规律；基于试验结果，建立岩溶作用下可溶岩裂隙损伤模型；基于可溶岩裂隙溶蚀－损伤耦合演化特征，结合岩溶作用下锚杆长期可靠性弱化机制，建立岩溶隧道围岩失稳致灾机制；根据岩溶隧道围岩失稳致灾机制，结合岩溶作用下可溶岩裂隙损伤模型、可溶岩宏观溶解速度与其损伤特性之间的定量关系以及岩溶作用下锚杆长期可靠性弱化规律，建立定量与定性相结合的可考虑岩溶作用对锚杆长期可靠性弱化影响的岩溶隧道运营期间围岩长期安全性趋势预测方法，并进行实际工程分析。该研究成果可为我国岩溶地区隧道工程的设计施工及安全运营提供重要的理论和技术支持。

岩溶是可溶性岩石（简称为可溶岩），特别是碳酸盐类岩石（如灰岩等）、硫酸盐类岩石（如膏盐岩等）受水溶蚀而形成的。在实施西部大开发战略过程中，遇到的挑战性问题之一就是如何解决岩溶对隧道等工程安全性的影响。本项目以岩溶隧道运营期间围岩安全性（围岩自身稳定性和支护结构长期可靠性共同作用结果）为研究目标开展系统研究。首先通过可溶岩细观力学试验、三轴压缩试验，建立了适合于描述可溶岩细观破坏机制和宏观力学特征的细观－宏观耦合的塑性损伤耦合模型；通过研制的岩溶作用下可溶岩损伤特性测试三轴仪，进行岩溶作用下可溶岩损伤特性测试，建立了可溶岩宏观溶解速度与其损伤特性之间的定量关系；通过研制的岩溶作用下锚杆长期可靠性弱化模拟测试装置，进行岩溶作用下锚杆长期可靠性弱化模拟测试，初步建立了岩溶作用下锚杆长期可靠性弱化机制与规律。继而，基于所建立的可溶岩力学模型（从细观-宏观耦合角度建立的可溶岩弹塑性损伤耦合模型以及从宏观力学角度建立的可溶岩塑性力学模型与层状可溶岩横观各向同性应变软化模型）以及岩溶作用下可溶岩损伤特性测试结果，建立了岩溶作用下可溶岩裂隙损伤模型。最后，根据岩溶隧道围岩失稳致灾机制，结合岩溶作用下地下工程可溶岩围岩力学稳定性计算分析方法以及初步建立的岩溶作用下锚杆长期可靠性弱化机制与规律，初步建立了定量与定性相结合的可考虑岩溶作用对锚杆长期可靠性弱化影响的岩溶隧道运营期间围岩长期安全性趋势预测方法。本项目所取得的研究成果可为我国岩溶地区隧道工程的设计施工以及安全运营提供重要的理论和技术支持。