既有线框构桥中间接长工程关键施工技术

Key Construction Techniques for Lengthening the Mid-Section of a Frame Bridge of an Existing Railway

新建邯济铁路至胶济铁路联络线工程桑梓店框构中桥中间接长工程,由于地下水丰富、地质条件差以及施工作业空间狭小,采用衬板防护路基既有框构桥中间接长的施工方案。为保证临近营业线的安全,采取停用一侧线路、设置隔离区域、采用分段拆除同时下沉挡土板防护路基等多种措施,介绍了既有护栏及悬臂结构的拆除、地基处理和基坑开挖等技术。与原设计架设便梁和打设钢板桩防护方案相比,降低了施工安全风险、缩短了施工工期、提高了经济效益,为今后类似复杂条件下的既有线桥涵接长施工提供了借鉴和技术参考。

As the underground water is abundant,the geological conditions are bad and the clearance for construction and opera-tion is small, the mid-section-lengthening project of the Sangzidian Frame Bridge of the railway tie line for the newly-built Han- Ji Railway and Jiao-Ji Railway adopts the construction scheme of protecting the sub-grade with scaleboards and lengthening the mid-section of the existing frame bridge. In order to ensure the safety of the neighboring railways in operation, we have the op-eration of the railways on one side ceased,and a separating zone provided,The old railways are removed section by section, in the meantime of which the retaining scaleboards are sunk to protect the sub-grade and quite a few other measures are taken. In-troduced in the present paper are the key construction techniques concerning the removal of the existing guardrails and the can-tilever structure,the treatment of the foundation, and the excavation of the foundation pit. Compared with the originally de- signed scheme,in which make-shift beams have to be erected and steel plate protective piles have to be driven, the present scheme helps lower the risks in construction safety, shorten the construction duration,and raise the economic benefit. The suc-cess in this project may serve as a useful technical reference for the lengthening construction of other bridges and culverts of ex-isting railways under similar complex conditions in the future.