The Study On Seepage Mechanism And Waterproofing Drainage Measures In Integral Multi-arch Tunnel

Due to its advantages in aspects of route selection and land requisition,multi-arch tunnel is widely applied to mountain tunnels and city tunnels.But multi-arch tunnel exist leakage phenomenon like other types of tunnel,especially in the integral multi-arch tunnels tunnel. Leakage will result in extremely adverse effects on structure safety and operating environment in tunnels , Proven integral multi-arch tunnel leakage mechanisms, forward key technical measures of tunnel construction and waterproofing drainage, can reduce water leakage phenomenon in new multi-arch tunnel.Through leakage investigation and numerical simulation analysis, obtain results as follows:â‘ Based on investigation analysis on seepage condition of tunnels in HangHui highway,Items that are mainly concentrated in the area of"three joints"and partition, manifested as linear and area-based leakage. Using AHP to analysis leakage of YuLingguan tunnel,known that the defects of waterproofing drainage design in mid-wall of integral multi-arch tunnel are the main reason of water leakage occurred in integral multi-arch tunnels.â‘¡Using Midas/GTS software to numerical simulation of construction phase in YuLingguan tunnel, the results show that the higher water level,the greater vault displacement,surrounding rock stress and surface settlement caused by tunnel excavation, the extent of seepage is more extensive by tunnel excavation, so groundwater is detrimental to excavation of tunnel; Another establishment of two-dimensional tunnel model,when the impermeability of reinforced surrounding rock have improved to a certain degree,the reinforced surrounding rock can reduce significantly leakage in tunnels, .â‘¢In various conditions of different groundwater water level and rock reinforced or not, numerical simulation of seepage in operational phase of multi-arch tunnel results show that: When different combinations of circular construction joints and longitudinal construction joints in mid-wall occurre water leakage, The higher groundwater water level,the more serious in construction joints leakage, it can significantly reduce the leakage when the surrounding rock is reinforced; Another when circular construction joints occurre leakage , effects on seepage is more serious,and the leakage in the wall of inside tunnel is the most serious.Finally through the characteristics and mechanism of integral multi-arch tunnel leakage,leakage field investigation and analysis in tunnels,numerical simulation analysis etc, Summarizes the control points of multi-arch tunnel leakage,and the key technical measures of waterproofing drainage design and construction in multi-arch tunnel.Integral multi-arch tunnel should put on "priority to waterproofing and more resistance in the tunnel structure;priority to plugging and combine waterproofing with drainage in the mid-wall" for the principle...