Box culvert construction method for broadening road and box culvert

Abstract

The invention discloses a box culvert construction method for broadening a road and a box culvert, the method comprises the following steps: calculating additional stress caused by self weight of a box culvert structure, and when the additional stress is greater than a first preset threshold, digging a soil layer with a certain thickness downwards; wherein the optimal thickness range is 1-3m, and then the road to be broadened above the tunnel is formed; performing filling on the two sides of the road to be widened and the outer side of the tunnel, and the filling boundary is a stable slope which forms a downward 30-degree included angle with the vertical direction and is tangent to the bottom edge of the tunnel; and constructing the box culvert with the stable slope and the side slope face as boundaries. According to the box culvert construction method for widening the road, the roadbed filling load of a newly-built widening road is reduced, the additional load of a tunnel structure and disturbance of tunnel surrounding rock are reduced, tunnel structure deformation cracking and differential settlement caused by filling construction above the tunnel are avoided, and the box culvert construction method has the advantages of being fast in construction, high in reliability and good in durability.

Description

technical field [0001] The invention relates to the technical field of road construction, in particular to a box culvert construction method for widening roads and the box culvert. Background technique [0002] At present, when widening roads, ordinary soil is often used for layered rolling to form the subgrade structure of the road; for the road widening project above the subway, affected by the buried depth of the tunnel structure and the small rigidity of the tunnel structure, if the filling in the widening process The process of soil loading may lead to uneven settlement or cracking of the tunnel structure below. In severe cases, it may cause the concrete structure of the tunnel structure to fall off and cause major risks of water and sand gushing. [0003] Under the existing technology, in order to solve the problem of excessive fill load in the road widening process above the subway tunnel, the form of a flyover bridge is usually used to cross the subway tunnel, and th...

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Problems solved by technology

[0002] At present, when widening roads, ordinary soil is often used for layered rolling to form the subgrade structure of the road; for the road widening project above the subway, affected by the buried depth of the tunnel structure and the small rigidity of the tunnel structure, if the filling in the widening process The process of soil loading may lead to uneven settlement or cracking of the tunnel structure below. In severe cases, it may cause the concrete structure of the tunnel structure to fall off and the risk of water and sand gushing will occur.

[0003] Under the existing technology, in order to solve the problem of excessive fill load in the road widening process above the subway tunnel, the form of a flyover bridge is usually used to cross the subway tunnel, and the load of the fill is converted into the self-weight load of the bridge structure, and the The self-weight load of the bridge structure is transmitted to the bottom through the piers and pile foundations to reduce the impact on the tunnel. However, the widening method provided by the prior art often has the following disadvantages: if ordinary soil is used for subgrade filling, the filling height is relatively high. When the filling height is too high, it may cause the additional stress of the subgrade self-weight load to the tunnel roof to fail to meet the relevant requirements. Even if lightweight concrete is used, the additional stress on the tunnel structure may be too high due to the high filling height, and the reliability is not strong and durable. If the bridge structure is used to cross the subway tunnel, affected by factors such as the deep buried depth of the tunnel and the difficulty of accurate positioning of the tunnel position, when implementing the pile foundation of the bridge structure, there may be insufficient verticality of the pile body and inaccurate positioning of the pile holes In severe cases, the tunnel structure may be punctured or damaged

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