在实际隧洞施工过程中隧洞突水突泥.docVIP

深埋隧洞开挖过程中突水与突泥的机理研究 摘要：突水与突泥是隧洞施工过程中常遇的重要工程灾难之一，本文利用离散元法，采用颗粒流PFC3D软件，结合流体动力学数值模拟的有限体积法，建立了由裂隙岩体及断层组成的围岩隧洞突、涌水三维数值模型，模拟隧洞突水、突泥的全过程；探讨了集中水源（断层）水压力、岩体裂隙性状等对隧洞突水、突泥的影响。据此提出了工程突水、突泥预防中两个重要的概念：突水临界水压力和前方临界突水间隔。并提出了隧洞突水、突泥的发生机理，以为突水发生的条件是存在集中的高压水源。水源压力的大小、开挖面至集中水源的间隔、岩体强度、岩体裂隙性状是影响突水的主要因素。 关键词：突水；突泥；离散元；裂隙岩体；颗粒流；隧洞 中图分类号：TV672 文献标识码：A文章编号：0559-9350（2011）05-0595-07 Study on mechanism of water burst and mud burst in deep tunnel excavation WANG Yuan，LU Yu-guang，NI Xiao-dong，LI Dong-tian Abstract：Water burst is one of the main disasters in the process of tunnel excavation. The software of PFC3D based Discrete Element Method （DEM） was A 3D numerical model including fractured rock and fault has been established. The whole process of water burst and collapsing due to tunnel excavation was simulated by using DEM and Computational Fluid Dynamics （CFD） . The influence of fault’s hydraulic pressure and fracture condition in rock on the quantity of water burst or collapsing was discussed. Two new conceptions—critical hydraulic pressure of water source and critical distance between excavation su***ce and water source were proposed. Finally， the mechanism of water burst and collapsing are concluded， i.e. the existence of water source with high water pressure is necessary for the occurrence of water burst，and pressure value of water source，distance between excavation su***ce and water source，and the mechanical property of rock and the fracture condition in rock mass are the main influencing factors. Key words：water burst；collapsing；DEM；fractured rock mass；particle flow；tunnel 1 研究背景 突涌水猜测题目一直是各类地下工程中普遍碰到的困难，无论是采矿巷道还是深埋隧洞，突水、突泥都严重威胁着工程的施工安全。由于突水、涌水是一个复杂的与时间有关的动态过程，影响因素众多，如地层岩性、地质构造分布、水文地质条件、初始地应力、施工方法等，在不同工程背景和地质条件下突水、涌水机理各异，因此突涌水研究一直是人们关注的热门和难点。 以往突水的研究以关注煤矿突水和岩溶突水较多，对于裂隙岩体深埋隧洞突水题目研究未几。早期常鉴戒地下采矿顶、底板突水方面的研究成果，如突水系数法［1］；“底板下三带”说［2］；零位破裂说［3］；岩水应力关系说［4］等。近年来有些学者对隧洞突水机理作了专门研究，取得了一些进展。刘宝臣等［5］从突水的不同特征上将岩溶涌突水机理分为直涌型、冲溃型和劈裂型三种类型；干昆蓉等［6］、李付法［7］采用水力劈裂理论研究了隧洞围岩破坏引起突水的机理。近期人们也开始采用基于连续介质力学的有限元法或有限差分