中文摘要：

以地下水位线以下的石楼隧道典型三趾马红土围岩段为例,通过现场监测对三趾马红土围岩的体积含水量、孔隙水压力、围岩应力（土压力）、拱顶沉降与水平收敛进行了分析。在此基础上,通过原位大剪试验获得了可靠的围岩抗剪强度参数,并建立了隧道三维有限元数值模型,分别对考虑水-力耦合效应、不考虑水-力耦合效应的三趾马红土围岩变形规律进行了探讨,分析了孔隙水压力随着隧道开挖的变化和三趾马红土围岩位移场、应力场受水-力耦合效应的影响程度,并提出了围岩破坏变形机制。结果表明：（1）实测拱顶下沉大于围岩水平变形,围岩应力可分为增长期（〈20d）、调整期（20~60d）、稳定期（〉60d）3个阶段,且整体应力水平较高,下台阶含水量大于上台阶,孔隙水压力经历了由负变正的过程。（2）现场剪切试验所测围岩的黏聚力为64.0k Pa,内摩擦角为27.7°。（3）数值分析表明,隧道开挖后孔隙水压力场变化十分明显,这是由地下水流速场的改变引起的,水力坡降在衬砌面附近最为明显,渗透动水压力导致土体产生一定的渗透变形;考虑水-力耦合后围岩剪应力、最大剪应变、拱顶沉降、水平收敛、底板隆起均较大。（4）受开挖及支护的影响,地下水产生渗流并依次经过拱顶、边墙,最终汇集于隧底;受开挖、地下水渗流的影响,围岩节理裂隙进一步扩张,成为地下水良好的运移通道;围岩的有效应力随着孔隙水压力的减小而增大,围岩的力学强度在土体趋于饱和状态时骤降,反过来,高有效应力、低围岩强度以及贯通性节理裂隙三者共同改变着地下水渗流场的状态。（5）为保障围岩整体稳定性,建议及时排出隧道底部积水并施做仰拱。

英文摘要：

Tunnel located in hipparion red clay region encountered many engineering geological problems in the construction process. In order to make sure construction safe and smooth traffic,a series of experiments and methods was carried out in the tunnel construction,such as laboratory test,field test and permeability test in situ,et al. Taking the surrounding rock section of the typical hipparion red clay in Shilou tunnel below the underground water level as an example,several aspects about the surrounding rock of hipparion red clay will be analyzed,including volume moisture content,pore water pressure,stress of surrounding rock（ soil pressure）,vault subsidence and horizontal convergence through the field monitoring. Based on this,a series of works will be done： the reliablesitu shear strength parameters of surrounding rock will be obtained by shear tests,three dimensional finite element numerical model of tunnel will be built,the deformation law of the hipparion red clay surrounding rock will be investigated respectively for the water-force coupling effect and without considering it,the variation of the pore water pressure during excavation,the influence degree about the displacement field and stress field of water-stress coupling on red clayrock will be analyzed,and the mechanism of the surrounding rock deformation will be proposed.The results show that：（ 1） The site monitoring vault settlement is greater than horizontal convergence,and the stress level of surrounding rock is higher on the whole,which can be described by using three different stages,the growth period（ 20 days）,the adjustment period（ 20 ~ 60 days）,the stable period（ 60 days）.Water content of the lower stage is higher than the top,the pore water pressure has experienced the process from negative to positive.（ 2） The cohesion determined by situ shear test C is 64. 0k Pa,the angle of internal φ is 27. 7°.（ 3） Numerical analysis shows that,the change of pore water pressure is very obvious after the tunnel excavation,which