Construction method for widening roadbed

Abstract

The invention relates to the technical field of civil engineering, in particular to a roadbed widening construction method which is technically characterized by comprising the following steps: S1, dismantling and cleaning; S2, excavating the old road: after the old road is removed, excavating the old road part in a stepped manner, and paving geogrids, wherein the step-type excavation step comprises the steps that S21, the slope toe part of the old road is excavated, that is, the height of the lowermost layer of step is 1 m, the width of the lowermost layer of step is 2 m, and original ground treatment is conducted after leveling, S22, after original ground treatment is finished, a first layer of 60cm gun slag is filled, impacted and rolled, after soil is filled to the top of a first step,a slope in the middle of the old road is excavated, the size and width of the middle step are larger than or equal to 1m, and the height of the excavated step is the filling thickness; S23, during roadbed top layer construction, excavation is conducted on the side, close to an old road soil shoulder, of the roadbed top layer, and during the period, soil layer filling is impacted and rolled once every 1.5 m thick; and S3, soil filling roadbed construction is conducted, specifically, a cross section full-width and longitudinal and horizontal layered filling compaction method is adopted.

Description

technical field [0001] The present application relates to the technical field of civil engineering, in particular, to a construction method for widening roadbeds. Background technique [0002] With the rapid development of my country's national economy, many two-way four-lane expressways built in the early stage of the country can no longer meet the existing traffic flow requirements. Expressway reconstruction and expansion projects have become a key issue in the development of expressways in recent years. The main direction of development is very necessary for the research on the reconstruction and expansion of expressways under various construction conditions. Development, the research on the widening of interchange ramps is an important aspect that urgently needs to be studied. [0003] Expressway expansion and widening projects are different from new projects, lacking corresponding norms and design standards, and there are many technical issues that need to be explored an...

AI Technical Summary

Problems solved by technology

[0006] (1) During the reconstruction of the old road, the spliced ​​road is different from the original road in terms of consolidation methods, foundation treatment, construction technology, and filler type. After years of operation, the settlement of the old road has been basically completed. Road and vehicle loads will inevitably cause additional settlement of the old road, which will lead to uneven settlement between the new and old roads, which will cause deformation of the joint between the old and new roads, and cracks and other diseases in severe cases;

[0007] (2) In terms of the number of layers of geotechnical materials laid, the inconsistency of the position and the depth of research, there is a big difference between the effect of geotechnical materials used in the splicing of new and old roads and the effect of theoretical engineering construction, and the settlement of the junction between the new roadbed and the old roadbed If the compensation measures are not well-taught construction measures, it can only be remedied through engineering and technical measures such as continuous reinforced cushion and reinforced embankment, geotextile anti-seepage and drainage in the later stage, which will affect the firmness of the splicing joint;

[0008] (3) When the new subgrade and the old subgrade are over-excavated to form the wide-faced steps, the previous slope-clearing operations are all asynchronous construction, so that during the foundation-building process, the step slopes on both sides form different stress-tension structures. At the same time, the slope dikes on both sides of the old subgrade have changed over a long period of time, and the angles of the slope dikes on both sides are different, which has caused certain difficulties in excavating and clearing the slope, thus affecting the laying of the new subgrade base.