Excavating method suitable for large section loess tunnels

Abstract

The invention provides an excavating method suitable for large section loess tunnels, and the excavating method is suitable for excavating loess tunnels with sectional areas more than 100 m2. The excavating method suitable for large section loess tunnels includes the following steps: a, diving soil bodies within the scope of tunnel excavation sections into an upper area, a middle area and a lower area, and firstly, excavating the soil body to form an E-shaped soil body in the upper area, b, excavating the E-shaped soil body simultaneously and keeping the depth of the E-shaped soil body within 2.5m to 3.0m, c, respectively excavating the soil bodies at the left side of the middle area, the right side of the middle area, the left side of the lower area and the right side of the lower area, d, keeping the excavating speed at each excavating surface the same, when the soil bodies at each excavating position being excavated, constructing preliminary bracing of the tunnels timely, and building formworks at positions, more than 20m away from soil body excavating surface in the lower area, of the bottom faces of the tunnels, and pouring permanent concrete linings of the tunnels. The method has the advantages that sinking and deformation of the tunnels are reduced, steal arches at vault positions are convenient to build, labor intensity is low, construction process is simple, construction cost can be reduced effectively, and construction process is accelerated. As shown in an attached map 3.

Description

technical field [0001] The invention belongs to the technical field of construction of large-section tunnels in soft surrounding rocks, in particular to the technical field of construction of large-section tunnels in loess strata. Background technique [0002] Loess has the characteristics of developing vertical cracks and low shear strength. Therefore, excavating tunnels in loess strata usually causes sudden collapse of soil and excessive deformation of supporting structures. Especially for excavation with cross-sectional area greater than 100m 2 of highway tunnels and high-speed railway tunnels, when they pass through the loess layer, the safety risk during tunnel construction is higher. In order to reduce the settlement and deformation of loess during tunnel excavation, prevent tunnel collapse, collapse and roof fall accidents, and ensure the safety of construction workers, excavation is usually carried out manually or mechanically, and the soil within the excavation sur...

AI Technical Summary

Problems solved by technology

[0008] In terms of the above-mentioned commonly used large-section loess tunnel construction methods, most of them need to set up temporary partition walls or cross braces, so that the tunnel construction process is complicated, resulting in slow construction progress, low efficiency, and high project cost

The circular excavation method with core soil does not need to set up temporary partition walls or cross braces, but the excavation section of the arch soil is large, and all the soil on both sides is excavated, which makes it difficult to erect steel arches at the arch Large, labor-intensive, and construction safety risks are also high, so it is necessary to find a new construction method that is economical and practical, and can ensure safe and fast construction

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