A construction method for strengthening and treating karst foundation of new railways and its subgrade structure

Abstract

The invention discloses a construction method for reinforcing a newly-built railway karst foundation and a roadbed structure thereof. The construction method comprises the steps of longitudinally constructing a plurality of rows of cast-in-situ bored piles along the railway line, wherein the cast-in-situ bored piles are formed through pouring reinforced concrete on site; longitudinally paving a plate girder prefabricated through reinforced concrete along the railway line above the cast-in-situ bored piles and at the top of a soft soil layer, wherein the tops of the cast-in-situ bored piles and the bottom of the plate girder are fixedly connected to form a pile plate structure; carrying out pressure grouting on the connection part of a hard soil layer and a karst layer of the karst foundation on the two sides of the pile plate structure, so as to form a longitudinal continuous grouting reinforcement zone along the railway line; and when the grouting reinforcement zone solidifies, paving a roadbed at the top of the plate girder. According to the roadbed structure provided by the invention, the karst foundation and an upper soil covering layer are reinforced, so that the foundation bearing capacity is improved, and the post-construction settlement of the roadbed is effectively controlled.

Description

technical field [0001] The invention relates to the field of geotechnical engineering, in particular to a construction method for reinforcing and treating karst foundations of newly-built railways and a subgrade structure thereof. Background technique [0002] Karst is a variety of geological forms, functions and phenomena produced by soluble rocks such as limestone and dolomite under the long-term dissolution of water. The main forms of deformation and failure of karst foundation include insufficient foundation bearing capacity, uneven settlement, foundation sliding, and surface collapse. With the development of social economy, railway construction is getting faster and faster, and more and more railway projects are carried out in karst areas. The smoothness and stability of subgrade structure are directly related to the safety of railway operation. Control has extremely strict requirements. Therefore, when building high-speed railways on karst foundations, it is necessar...

AI Technical Summary

Problems solved by technology

The padding method is mainly suitable for exposed karst and shallow buried karst, but not for covered karst and deep buried karst; grouting method is the most commonly used karst treatment method, but it can only ensure the stability of karst foundation, and cannot Good control of post-construction settlement; the high-pressure rotary spraying method has high requirements for construction technology, construction machinery and equipment, and materials, including construction experience, and is not economical, so it has not been widely used

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