Construction method for obliquely downwards penetrating high-speed rail bridge through U-shaped frame structure

Abstract

The invention discloses a construction method for obliquely downwards penetrating a high-speed rail bridge through a U-shaped frame structure. The method comprises determining the position of a foundation pit; performing high-pressure jet grouting pile construction below the foundation pit and on the to-be-jacked path of the U-shaped frame structure; excavating a foundation pit of which the bottomsurface has a gradient and the excavation depth is lower than the setting depth of the U-shaped frame structure below the high-speed rail bridge; prefabricating the U-shaped frame structure; and jacking the U-shaped frame structure into the to-be-jacked path in a downhill mode while soil is excavated. The method has the advantages that the maximum floating value of the bridge pier is minimum, themost adverse effect duration is shortest, and the caused differential settlement of the bridge pier is also minimum. The construction period is short, the excavation depth of the soil body under thebridge is small, and it is guaranteed that replacement of the soil body under the bridge is completed within the shortest time. In the construction process, soil is excavated from the U-shaped frame structure, and the direction and elevation of the U-shaped frame structure are easy to control. The jacking construction process is safe and controllable, continuous operation can be achieved, if piertop upheaval occurs, balance of soil pressure can be controlled in time in a U-shaped frame structure jacking weight mode, and therefore operation safety of the high-speed rail can be guaranteed.

Description

technical field [0001] The invention belongs to the technical field of construction of existing high-speed rail bridges passing under roads, and in particular relates to a construction method for U-shaped frame structures obliquely passing down high-speed rail bridges. Background technique [0002] With the rapid development of my country's economic construction, the construction of high-speed rail has gradually increased. Therefore, the situation of high-speed rail "dividing" cities and roads is becoming more and more obvious. At present, due to the high-speed train operation speed of the high-speed rail, the stability requirements of its bridges and piers are extremely high, and changes of more than 2mm are not allowed. Therefore, when the road crosses the existing high-speed rail line construction, how to ensure the operation safety of the high-speed rail is the key point in choosing the construction method. [0003] According to relevant domestic and foreign materials a...

AI Technical Summary

Problems solved by technology

The construction method of the cast-in-place box under the high-speed railway bridge is to excavate the foundation pit under the high-speed railway bridge, and then in the foundation pit, from both sides of the high-speed railway bridge to the center, the U-shaped frame structure is symmetrically cast in place section by section, which is similar to the construction method of the flat slope jacking box. However, the disadvantage of this construction method is that the construction period is long, and when the foundation pit is exposed for a long time and the depth of the foundation pit is large, it will have a greater impact on the high-speed railway pier

In terms of construction difficulty, during the construction process, due to the narrow space for excavation and excavation near the high-speed railway bridge, only one section can be constructed at a time, and continuous operation is not possible. Moreover, the space for excavation, material transportation, and concrete pouring is narrow. construction difficulties

In terms of the safety of high-speed rail, the bottom of the high-speed rail bridge is usually about 4.5m from the ground, and construction machinery will cause safety hazards to both the protective piles and the high-speed rail bridge, and the exposure time of the construction foundation pit is relatively long, and there are relatively few control measures, mostly passive measures , the risk to the safe operation of the high-speed rail is relatively large, so it is only suitable for use under the condition that the clear height of the bridge bottom of the high-speed rail bridge can meet the operation of construction machinery

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