Experimental methods and models for the impact of highway expansion construction on existing structures

Abstract

The invention provides a test method and model for the influence of highway expansion construction on existing structures. The test model includes a cement layer, a reinforced concrete layer, and a temporary support layer arranged in sequence from top to bottom. The temporary support layer is a sulphur mortar prefabricated plate with built-in heating pipes. The periphery is exposed, and the bottom of the exposed part is supported with an electro-hydraulic variable stiffness device. The electro-hydraulic variable stiffness device is located on the base. The base is provided with a foundation pit under the temporary support layer. The edge of the temporary support layer It is overlapped on the edge of the foundation pit, the bottom of the foundation pit is fixed with a pipe pile whose top is pre-buried in the temporary support layer, and the top surface of the pipe pile is abutted against the bottom of the reinforced concrete layer. The invention utilizes the variable rigidity of the variable rigidity device and the releasable characteristics of the temporary support layer to achieve the purpose of applying a variable load to the existing structure model on the cement layer, thereby realizing the realization of the impact of highway expansion on the existing structure. chemical test.

Description

technical field [0001] The invention relates to a test method and a model for the influence of highway extension construction on existing structures. Background technique [0002] The proposed provincial highway S364 Jiangmen Wuyi Road expansion project is an existing road expansion project that crosses the urban area, along which there are a large number of residential buildings, industrial plants and the Jiangmen branch line of the Guangzhou-Zhuhai Intercity Railway. Among them, the mileage of the parallel section of the railway is K63+719~K67+762. The Jiangmen Branch Line of the Guangzhou-Zhuhai Intercity Railway is a railway that has an important impact on the economic development of the Jiangmen area. Its design speed is 200km / h, and the railway level is National Railway Class I. , High-speed rail (reserved), the scale of the railway is double-line electrification, and the railway is positioned as an intercity railway and a national trunk line railway (forward). How to...

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Problems solved by technology

[0005] Since the existing railway bridge site is relatively close to the construction site of the high-pressure jet grouting pile, the soil around the pile will be squeezed and deformed to the outside when the high-pressure jet grouting pile is constructed, and the foundation pile of the existing railway bridge can bear a large vertical load , but cannot bear large lateral loads. In this case, under the action of lateral soil extrusion, the bridge foundation piles are prone to deflection and deformation, resulting in deflection of the bridge pier, causing horizontal displacement or even rotational displacement of the upper beam of the bridge.

Due to the deviation of the upper load action position, the deflection of the bridge foundation pile will be further aggravated, resulting in the risk of cracking or even fracture of the potential foundation pile

At the same time, when the high-pressure jet grouting pile construction section is close to the pile foundation of the existing railway bridge, the displacement of each pile foundation shows a large difference, which causes non-uniform displacement of the beam body in the longitudinal direction of the line

Under the construction pressure of high-pressure jet grouting piles, due to the soil-foundation pile-bridge interaction, it will inevitably cause smoothness problems and geometric state deterioration of the track on the bridge, which will directly affect the safe operation of the train on the bridge

[0006] Existing studies on the impact of highway expansion construction on existing structures are mostly limited to theoretical analysis of mechanics using finite element software, and few studies have been conducted through experiments, mainly because there is no one that can well simulate the impact of highway expansion construction on existing structures. There are test models affected by structures, so there is an urgent need for a method and model that can well simulate the impact of existing highway expansion construction on existing structures

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