Soft soil area roadbed widening structure and construction method thereof

Abstract

The invention belongs to the technical field of roadbed widening and relates to a soft soil area roadbed widening structure and a construction method thereof. The soft soil area roadbed widening structure comprises an old roadbed, a gravel cushion layer, a soft soil stratum and a lower lying supporting layer which are arranged successively from top to bottom and further comprises vertical pile bodies, connecting pieces and reinforced retaining walls. The vertical pile bodies punch through the soft soil stratum and are supported on the lower lying supporting layer; the gravel cushion layer is laid on the tops of the vertical pile bodies; steps are arranged in the position, on a slide slope after substantial slope cutting, of the old roadbed; the slope ratio of the slide slope after slope cutting is (1:0.5)-(1:1); the reinforced retaining walls are arranged on the gravel cushion layer and are buckled with the steps of the slide slope of the old roadbed; and the connecting pieces are placed on the combination parts of the reinforced retaining walls and the old roadbed and are connected with the reinforced retaining walls and the old roadbed correspondingly. The invention provides the roadbed widening structure and the construction method thereof, the occupied area is small, the foundation treatment cost is low, the filler requirement is few, construction efficiency is high, the structure is stable, and the roadbed widening structure and the construction method thereof are especially suitable for roadbed widening engineering in coastal soft soil areas.

Description

technical field [0001] The invention belongs to the technical field of roadbed widening, and relates to a roadbed widening structure and a construction method thereof, in particular to a structure suitable for expressway roadbed widening in coastal soft soil areas and a construction method thereof. Background technique [0002] There are many technical problems in the roadbed widening project of expressways in soft soil areas. If they are not properly handled, they will easily lead to longitudinal cracks in the road surface, pavement undulations, and even the overall instability of the widened part. , pile (over)load preloading or both methods for foundation treatment. In some deep soft soil areas, subgrade settlement is still in the process of development. At this time, CFG piles, reinforced concrete piles and prestressed pipe piles are blindly used. The pile composite foundation will cause the foundation reinforcement strength of the widened part to be too large, causing t...

AI Technical Summary

Problems solved by technology

At present, the measures in these three aspects are widely used in actual projects, and measures 1) and 2) are generally adopted at the same time, but the "slope cutting" in the existing measures is limited to the removal of loose soil on the slope of the old roadbed , the new subgrade is almost entirely built on the original foundation. At this time, not only the original foundation needs to be treated, but also the foundation treatment under the old subgrade slope cannot be ignored. The foundation is reinforced, resulting in a substantial increase in the cost of foundation treatment

At the same time, in coastal areas with developed economy and high degree of urbanization, Nu Skin roadbed still adopts a slope ratio of 1:1.5, which will highlight the following disadvantages: ① The cost of land acquisition and demolition will rise sharply, and land acquisition will even be impossible, which will seriously slow down the progress of the project; ② There is a large demand for filler, not only the cost is high, but also the additional stress of the foundation caused by the new roadbed is also relatively large, which in turn puts forward higher requirements for foundation treatment

The lightweight filler in measure (3) can be conveniently built into a vertical embankment, but the application time in China is still short, and it is still in the stage of experience accumulation. Although some technical regulations have been formulated, specific projects still need to be treated in detail, and the design The requirements for construction and construction levels are high, and the applicability of lightweight fillers under the action of extra-heavy and extremely heavy traffic loads needs further research

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