深埋岩溶隧道掌子面突水灾害可靠性上限分析∗

旨在研究高地应力、高压富水条件下深埋岩溶隧道掌子面突水灾害的可靠性问题。基于已有研究成果，考虑高地应力以及高压富水地质条件，采用极限分析上限法构建了以剪切破坏为主的深埋岩溶隧道掌子面三维防突机制。根据虚功率原理建立突水破坏过程中的能量方程，利用Hoek-Brown 强度准则求解了高地应力以及高压富水条件下防止掌子面突水所需要的支护力上限解。在极限破坏状态下，根据掌子面上施加的支护力与突水破坏时的围岩压力构建极限状态方程，建立了深埋岩溶隧道掌子面防突可靠度模型，并采用响应面法计算了掌子面发生突水灾害的失效概率。分析了水平地应力、溶腔水压力、岩体强度参数以及隧道洞径对支护力、潜在破坏长度的影响规律，给出了满足不同容许失效概率下深埋岩溶隧道预防突水灾害所需要的最小支护力以及在有限支护效应下能抵抗的最大破坏长度。将研究成果应用于实际工程案例中，与已有研究、现场结果相比较，验证了本文计算结果的有效性，可为今后类似深埋岩溶隧道的防突问题提供理论指导和参考。

Reliability Analysis of Water Inrush Disaster Prevention at Faces inDeeply Buried Karst Tunnels Based on Upper Bound Theory

The study aims to analyze the reliability of water inrush disaster prevention at faces in deep-ly buried karst tunnels under high ground stress, high-pressure and water-rich conditions. Built uponexisting research and the geological environment, a 3D outburst prevention mechanism for the tunnelfaces, primarily based on shear failure, was constructed using the upper bound analysis method. Anenergy equation for the water inrush failure process was established based on the principle of virtualwork rate. The Hoek-Brown strength criterion was used to determine the upper limit solution for thesupport pressure required to prevent water inrush in tunnel faces under high ground stress, high-pressure, and water-rich conditions. Under the state of extreme failure, a limit state equation was estab-lished based on the support pressure applied to the tunnel faces and the surrounding rock pressure atthe time of water inrush failure. A reliability model for outburst prevention at the faces of deeply buriedkarst tunnels was established. To determine the likelihood of water inrush disasters at tunnel faces,the response surface method (RSM) was applied. The effects of horizontal ground stress, water pres-sure in dissolution cavities, rock mass strength parameters, and tunnel diameter on support pressureand potential failure length were analyzed. The minimum support pressure required to prevent waterinrush disasters in deeply buried karst tunnels under different allowable failure probabilities and themaximum damage length that could be resisted under limited support effectiveness was provided. Ap-plied to practical engineering cases and compared with existing studies and field results, the findingsconfirm the effectiveness of the calculated results, offering theoretical guidance for preventing outburstproblems in similar deeply buried karst tunnels in the future.