Exploratory Research on Drainage Structure of Highway Tunnel Based on Reducing the Risk of Crystallization Blockage

Abstract

Crystal blockages of tunnel drainage systems severely undermine the tunnel lining structure and operation safety. In order to reduce the risk of crystal blockages of tunnel drainage systems, the distribution of highway tunnel defects was identified through a field survey, indoor test, and literature analysis, and an optimization method of tunnel drainage structures was proposed. The research suggested the following: (1) Lining water leakage and construction joint water leakage were the most common defects in the tunnel drainage system of Renhua–Xinfeng Expressway and Yingde–Huaiji Expressway in Guangdong Province, accounting for 60% and 32% of total defects, respectively. The number of defects that occurred in the drainage system of the tunnel was larger in the granite formation, with the number of road seepage and inspection chamber crystallization incidents reaching 2.5/km and 2.8/km, respectively. (2) The groundwater was mainly alkaline with a pH value of 8~12, Ca2+ (107 mg/L) was the cation with the largest ion concentration, and HCO3− (165 mg/L) was the anion with the largest ion concentration. The crystals in the tunnel drainage system were predominantly square, spindle, and rhombic calcite and aragonite composed of CaCO3, mixed with a small amount of sediment. (3) To reduce the risk of crystal blockages of the tunnel drainage system and ensure tunnel lining structure safety, a threefold optimization measure was proposed, namely, setting one-directional drainage pipes between the cable trench and the roadside blind drainage ditch, applying “π” type anti-crystallization drainage water-stop belts at the circular construction joints in the secondary lining, and both increasing the slope of the transverse drainage pipe and using an anti-crystallization drainage pipe. The research results will play an important role in guiding the design, construction, and maintenance of highway tunnel drainage systems in China.

Study on the crystallisation formation mechanism and breakage of tunnel drainage system in dolomite area

“…Figure 1 depicts the crystallisation that was created at various locations in the tunnel. It has been shown that lining leakage and construction joint leakage are the most common defects in most highway tunnel drainage systems and that the subsurface water is mainly alkaline, with Ca 2+ (107 mg L −1 ) being the cation with the highest ion concentration and HCO 3 − being the anion with the highest ion concentration 3 . In the field of tunnelling, many studies on karst have been reported 4–6 ; Tao 7 discovered that dolomite contains CaO, MgO, Al 2 O 3 and other substances.…”

“…À being the anion with the highest ion concentration. 3 In the field of tunnelling, many studies on karst have been reported [4][5][6] ; Tao 7 discovered that dolomite contains CaO, MgO, Al 2 O 3 and other substances. Xie and Rao et al 8,9 conducted an experimental study on the composition of dolomite and found that the main component of dolomite is CaCO 3 and contains MgO and Al 2 O 3 , which have a great influence on the physical properties of dolomite.…”

Research on the Temperature Field and Water Discharge Around Different Drainage Structures for the Cold Tunnel

“…Kim et al (2018) studied the causes of water seepage in highcold tunnels and developed new tunnel drainage structures to optimize their layout. In addition, Liu et al (2022) investigated the distribution of defects in highway tunnels through on-site investigation, indoor experiments, and literature analysis to propose optimization methods for tunnel drainage structures to reduce the risk of crystal blockage in tunnel drainage systems. Ji et al (2012) suggested connecting the circular drainage pipe directly to the central drainage pipe and installing a strip insulation layer in areas with water-rich surrounding rocks and where the middle and lower parts of the circular drainage pipe are prone to freezing.…”

Change of temperature field around different drainage structures in cold region tunnel based on model testing

“…Liu et al 16 introduced the basic principles, ideas, and specific measures for the treatment of diseases such as water leakage, insulation, and lining reinforcement in the Dabanshan cold Tunnel by analyzing the causes of the diseases of tunnels. To reduce the risk of blockage in the tunnel drainage system, Liu et al 17 determined the distribution of defects in highway tunnels through on-site investigation, indoor experiments, and literature analysis, and proposed an optimization method for tunnel drainage structure. Ji et al 18 proposed that the circular drainage pipe should be directly connected to the central drainage pipe, and a strip insulation layer should be installed in areas where the surrounding rock is rich in water and the middle and lower parts of the circular drainage pipe are prone to freezing.…”