A Construction Method for Shallow Buried Tunnels in Loess Gullies

Abstract

The invention discloses a construction method of a shallow-buried tunnel in a loess gully. The construction method comprises the following steps: 1, grouting a sleeve valve pipe for advancing reinforcement: carrying out sleeve valve pipe grouting for reinforcement on a stratum in the construction area of the constructed shallow-buried tunnel; 2, carrying out tunnel excavation and preliminary bracing; and 3, constructing a second lining. The construction method is simple in step, reasonable in design, simple and convenient in construction and excellent in using effect; the sleeve valve pipe isadopted and a plurality of rows of grouting holes are adopted to grout the reinforced stratum for reinforcement; the range of the reinforced stratum is specifically limited; both the tunnel hole bodyand the tunnel base can be reinforced, and the reinforcement effect is reliable; the shallow-buried tunnel construction method is particularly suitable for advancing reinforcement and excavation construction of the shallow-buried tunnel section which is positioned in a loess gully and is adjacent to an earth and stone interface, and the earth's surface of the shallow-buried tunnel is a silting-upland layer. The construction method can effectively ensure safety and reliability of the excavation process of the shallow-buried tunnel in the loess gully, can effectively improve the stability of the excavated tunnel hole and can effectively improve the bearing force of the tunnel base.

Description

technical field [0001] The invention belongs to the technical field of tunnel construction, and in particular relates to a construction method for a shallow-buried tunnel in a loess gully. Background technique [0002] The valley is a trough-shaped depression formed by the erosion of the storm. The small one is only more than ten meters long, and the large one can reach tens of kilometers. Bursts are mostly formed by the collection of sheet flows on slopes, because the surface on slopes is not flat, so there are local low and flat depressions. In the depression, the flowing water particles on both sides and upstream of it converge to the lowest point in the middle to form a flow center line. When the water layer thickens, the flow velocity increases, and the scour capacity increases, the depression is gradually scoured and deepened to form a valley. and ravine water. According to the size and development shape of the valley, it can be divided into four main types: rills, c...

AI Technical Summary

Problems solved by technology

Alluvial soil is the soil formed by accumulating in still water or slow flowing water. The soil in the alluvial soil layer is alluvial soil with a high moisture content (the moisture content is usually above 20%). Vertical cracks are developed. The jacking block is large and loose, so it is very easy to cause the collapse of the face and the large deformation of the initial support structure. The construction risk is high and the construction is difficult

[0006] 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

Loess tunnels during the operation period, especially heavy-duty railway tunnels, are prone to settlement and deformation of the base under the long-term train vibration load, which will lead to deterioration of driving conditions and endanger driving safety in severe cases

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