Construction method of entrance section of loess tunnel passing through landslide

Abstract

The invention discloses a construction method of a loess tunnel entrance section through a landslide mass. The method comprises the following steps that 1, an entrance soil layer is pre-reinforced; 2,a tunnel entrance is constructed; 3, excavation and initial support construction is conducted on the reinforced tunnel section; 4, a reinforced tunnel section base is reinforced; 5, the reinforced tunnel section is subjected to secondary lining construction; 6, excavation and initial support construction is conducted on a rear side tunnel section; and 7, the rear side tunnel section is subjectedto secondary lining construction. The method is reasonable in design, simple and convenient to construct and good in use effect, cement-soil mixed piles are adopted for pre-reinforcement before excavation, a construction process of the tunnel entrance section through the landslide mass is guaranteed to be safe and reliable, meanwhile, the tunnel entrance section is excavated by adopting a three-step excavation method, the reinforced tunnel section base is reinforced, an excavation process of the tunnel entrance section through the landslide mass can be guaranteed to be safe and reliable, in addition, the influence on the stability of a soil layer on the circumferential side of the tunnel entrance is small, and the stability of the excavated and formed tunnel entrance can be effectively improved.

Description

technical field [0001] The invention belongs to the technical field of tunnel construction, and in particular relates to a construction method for the entrance section of a loess tunnel passing through a landslide body. Background technique [0002] Loess refers to deposits of yellow silt that were transported by wind during the Quaternary period in geological age. Loess collapsibility coefficient (also called collapsibility coefficient) is a mechanical parameter for evaluating the collapsibility of loess. It means that under a certain pressure, the loess collapsibility coefficient refers to the ratio of the difference between the height of the soil sample before and after immersion and the original height of the soil sample. Loess collapsibility coefficient is an important index to evaluate the collapsibility of loess, which can be directly measured by experiments. According to the different collapsibility coefficients of loess, loess can be divided into collapsible loess ...

AI Technical Summary

Problems solved by technology

[0006] The construction of the entrance section of the loess tunnel passing through the landslide is very difficult, especially when the entrance section of the tunnel is located in the front of the landslide, the construction difficulty is even greater. After analysis, the main problems are as follows: Inducing the sliding of the landslide body can easily bring safety hazards and interference to the tunnel construction; second, the tunnel entrance (ie, the tunnel entrance) is located at the front edge (ie, the front) of the landslide body, and the infiltration of surface water makes the water content of the new loess higher , the slope of the tunnel entrance and the excavation of the open tunnel cannot guarantee its stability, and landslides are extremely prone to occur; third, when the tunnel dark tunnel passes through the landslide body, it is easy to cause disturbance to the landslide body during the excavation operation, so that the tunnel body is in contact with the landslide Under the interaction of different bodies, dislocation will be generated, which will lead to the destruction of the tunnel structure; fourthly, after the excavation of the tunnel body, the water on both sides of the tunnel body will flow to the tunnel body for discharge. shift

In addition, due to the special mechanical properties and structural characteristics of loess, the poor stability and low bearing capacity of surrounding rock have become the main problems faced by loess tunnel construction

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