Localized Water Pressure (LWP) on tunnel means water pressure concentrating on partial areas of tunnel periphery instead of distributing evenly all around tunnels. High LWP generally occurs in tunnels crossing mountain areas with faults and fracture zones or results from clogging of the water drainage system of tunnels. High LWP on tunnels could lead to severe structural cracks and leakages. A mountain tunnel in fracture zones with LWP of nearly 2 MPa was taken as an example to investigate the acting mechanism and effect of LWP on the safety of the tunnel lining during the whole process of the tunnel crossing through the fracture zone by a 3D Ground-Structure modeling. The main conclusions drawn from the research work are as follows: (1) The LWP acting on the tunnel lining dynamically changes in both magnitude and distribution (longitudinal and cross-sectional) with the advance of the tunnel face. The magnitude of LWP in the fracture zone is up to 17.9 times higher than that outside the fracture zone and can lead to damage to the tunnel structure. The main distribution scope of the LWP on the lining structure is within 8 m from the boundary of the fracture zone. (2) The actual internal forces of lining near the tunnel face are highest, and the tunnel structure in the fracture zone and within 16 m outside the fracture zone is at risk of crushing induced by high LWP. (3) Cutoff grouting is effective in reducing the LWP and the axial force remarkably with a decrease of 52.4% and 76.8%, respectively. The necessary thickness of the grouting ring for the tunnel crossing fracture zone is set to 6 m. (4) A novel drainage network was proposed to improve the reliability and sustainability of the drainage system of the tunnel in the fracture zone with high water pressure. The results of this study provide practically useful suggestions for the design and construction of mountain tunnels crossing fracture zones of high LWP.

隧道上的局部水压（LWP）表示水压集中在隧道外围的部分区域，而不是均匀分布在整个隧道周围。高LWP通常发生在穿越有断层和断裂带的山区的隧道中，或者是由于隧道排水系统的堵塞造成的。隧道的高LWP可能导致严重的结构裂缝和渗漏。以LWP接近2 MPa的断裂带中的一条山隧道为例，研究了3D Ground-LWP在穿过断裂带的整个隧道穿越过程中，LWP对隧道衬砌安全性的作用机理和影响。结构建模。从研究工作中得出的主要结论如下：（1）随着隧道工作面的推进，作用在隧道衬砌上的LWP的大小和分布（纵向和横截面）都会动态变化。裂缝区的LWP值比裂缝区外的LWP高17.9倍，并可能导致破坏隧道结构。LWP在衬砌结构上的主要分布范围在距裂缝带边界8 m之内。（2）隧道工作面附近衬砌的实际内力最高，裂缝区和裂缝区外16 m以内的隧道结构存在高LWP引起压溃的危险。（3）截断灌浆有效地降低了LWP和轴向力，分别降低了52.4％和76.8％。隧道穿越断裂带的注浆环的必要厚度设置为6 m。（4）提出了一种新型的排水网络，以提高高水压裂缝带隧道排水系统的可靠性和可持续性。研究结果为穿越高LWP断裂带的山地隧道的设计和施工提供了实用的建议。