Geogrid Technology in Road Widening and Widening Construction
Abstract: The differential settlement of subgrade is a common problem in the construction process of road subgrade widening. To this end, taking the actual project as an example, the principle of wholesale polyester geogrid reinforcement is expounded, and the construction technology of polyester geogrid for sale in the road widening and widening construction is analyzed and discussed, including construction preparation work, laying the bottom high quality polyester geogrid, laying the upper geotechnical Grid and drainage construction measures, etc., to improve the bearing capacity of the subgrade, avoid the problem of subgrade settlement, and ensure the construction quality of the subgrade engineering.
Keywords: roadbed widening; high quality polyester geogrid; settlement treatment
1. Project Overview
The G319 Wulingshan-Chadong Highway Reconstruction Project (Huayu Section) starts at K1677+600 on the G319 National Highway and is the junction of the Jiebi Township of Huayuan County at the junction of Jishou City and Huayuan County. The starting point is K0+000. The route is basically laid along the old road of G319 National Road. It passes through Ma Lichang Township, Huayu Town, Tuanjie Town, and Biancheng Town. The endpoint is at the Huainan Bridge Head of Hong’an Bridge at the junction of Huayuan County of Hunan Province and Xiushan County of Chongqing. The terminal number is K55+074.952. The length of the line is 55.08km. The project adopts the two-way two-lane secondary road standard. The subgrade width is divided into two standards of 8.5m and 10.0m, and the design speed is 60km/h. The subgrade of the project mainly adopts a half-width widening method, supplemented by widening on both sides. According to the design, in the embankment section, a total of 1 to 3 geotechnical cells are laid according to the steps, and the steps are overlapped. The laying positions are preferentially the bottom surface of the roadbed (the uppermost step) and the bottom surface of the embankment (the lowermost step). Steps in the middle of the two layers. The mesh belt connection of the geocell is made by U-shaped steel nails. The diameter of the U-shaped nail is 8mm, the outermost steel nail is 20cm away from the edge of the compartment, and the laying surface of the geocell is flat. There must be no slabs, etc. The hard protrusion, the maximum particle size of the roadbed filler within 10cm from the geocell is ≤12cm. When laying the net, it should be pulled into place, landfilled in time, and it is strictly forbidden to expose to the sun. The connection between the nets can be done by a professional plug-in or on-site connection. This article takes this project as an example to analyze and discuss the wholesale polyester geogrid construction technology.
2. Geogrid reinforcement principle
Geogrid reinforcement technology is a common technique used in the construction of roads to expand and expand roadbed widening. It can be generally divided into glass fiber wholesale polyester geogrid, steel geogrid, polyester geogrid factory price, glass fiber polyester geogrid for sale. Grid. From the perspective of processing methods, high quality polyester geogrid can be divided into two-way geogrid and one-way polyester geogrid manufacturers; from the perspective of material type, polyester geogrid manufacturers can be divided into glass fiber grating and polyester geogrid factory price. In general, polyester geogrid factory price is mainly used to reinforce soft soil roadbeds, retaining walls, embankments, etc. By using a geogrid for reinforcement, the bearing capacity and stability of the subgrade structure can be significantly improved. As a flexible material, the polyester geogrid factory price can withstand relatively large tensile forces. By arranging the high quality polyester geogrid in the tensile deformation zone of the soil, the tensile stress of the soil can be effectively transmitted, and the steel structure is formed into a tensile member. Under the influence of load factors, the friction between the soil and the polyester geogrid manufacturers will restrict the lateral deformation of the soil to a certain extent. Due to the large degree of adhesion between the soil and the high quality polyester geogrid, the shear stress and tensile strength of the structure are improved, the joint position of the old and new roadbed and the settlement of the cross-section of the embankment are improved, thereby preventing lateral cracks and longitudinal directions. The purpose of the crack.
3. Application of geogrid construction technology in road widening and widening construction
3.1 Construction preparation work
Before the construction of the wholesale polyester geogrid, it is necessary to understand the climatic conditions, hydrological conditions, geological conditions, etc. of the area where the reconstruction and expansion project is located, and collect relevant data to fully understand whether the subgrade pavement has collapsed and tumbling, and then combine The design situation selects the corresponding treatment measures. The staking measurement of the construction site is carried out, and the embankment slope and the ground side pile of the highway subgrade are discharged, and then the elevation of the roadbed cross-section of the widened road section is measured to ensure that the data and the elevation in the drawing are consistent. When the access is relatively large, the inspector should immediately report it to the supervision engineer. Secondly, it is necessary to level the construction site to ensure that the flatness and compaction of the subgrade can meet the requirements.
3.2 Geogrid laying
During the road widening and construction process of the road reconstruction and expansion, the design uses a wholesale polyester geogrid with a size of 30×40mm for construction. During the construction, the construction shall be carried out according to the parameters in Table 1. During the roadbed widening operation, it is necessary to use a plastic polyester geogrid for sale with a tensile strength of 30 kN/m to lay the surface of the bed along the slope of the bed according to the actual situation of the currently widened section. The separation distance between the geogrids It is 0.6m. There is no need to lay a high quality polyester geogrid between the gravel cushions. For the section with the roadbed filling height >4m, the high quality polyester geogrid should be laid along the slope foot to the surface of the bed. The tensile strength of the polyester geogrid manufacturers is 30kN/m and the separation distance is 1.2m. In addition, in the geogrid laying operation, it is necessary to laterally lay the polyester geogrid factory price according to the widening direction of the roadbed, and ensure that the length of the polyester geogrid manufacturers laid can meet the requirements of widening the width of the designed roadbed. Geogrid overlap and distortion are not allowed during construction. When the roadbed is widened, the weeds on the surface must be cleaned up for the open flat section or the wrong slope. After the slopes are finished, the cushions are laid on the surface of the roadbed, and then the polyester geogrid manufacturers are placed. The polyester geogrid factory price is laid next to the lower deck along the widened section of the subgrade. When constructing the polyester geogrid manufacturers, it is necessary to carry out the laying of the geogrid in strict accordance with the design requirements by seaming or lap jointing and then leveling the polyester geogrid factory price to ensure that the laying width of the geogrid can meet the design requirements.
When laying the underlying polyester geogrid for sale, it is necessary to mark the scope of the wholesale polyester geogrid with the wooden stake and then lay the geogrid. When the underlying roadbed is widened, it is necessary to ensure the smoothness and smoothness of the polyester geogrid manufacturers and to keep the width of the geogrid consistent with the width of the subgrade. The bottom geogrid is joined using a seaming method. In the actual construction, the polyester geogrid factory price of the bottom layer can be interwoven and stitched by using the polypropylene strip interweaving seam with relatively strong strength in combination with the actual situation of the project. In addition, it is also possible to use lap joints for connection and to fix the grid with “U” nails to ensure that the polyester geogrid manufacturers are not twisted and wrinkled when laying the polyester geogrid for sale. The lap width of the high quality polyester geogrid should be controlled at 20m. the above. After laying the bottom polyester geogrid factory price, first, roll the materials on both sides, then roll the middle filler. After the earthwork is completed, the roller compactor and the bulldozer are used for rolling to ensure that the compaction construction quality can meet the compaction requirements when the roadbed is widened.
3.2.2 Upper geogrid laying
After the construction of the bottom layer is completed, and the construction quality of the bottom wholesale polyester geogrid can meet the construction requirements, the upper polyester geogrid manufacturers can be laid. The polyester geogrid factory price is laid in the same way as the connection method when widening the upper road surface. It should be noted that the top width of the fill layer and the width of the high quality polyester geogrid should be consistent. In addition, after the reinforced polyester geogrid for sale is laid, the earthwork filling operation needs to be carried out according to the rolling requirements and the filling thickness to ensure that the construction quality of the soil layer can meet the requirements of the roadbed widening construction quality.
3.3 Drainage construction measures
In the reinforcement of the highway subgrade, when using the wholesale polyester geogrid for reinforcement construction, in order to ensure the reinforcement effect of the polyester geogrid for sale, it is necessary to do the roadbed drainage treatment. In the drainage construction, it is necessary to arrange drainage facilities and filtration in the soil. Water facilities.
3.4 Combined position settlement treatment
(1) Treatment of the joint part of roadbed filling and excavation
In the case of roadbed filling and excavation combined with position treatment, the two-way 40kN/m wholesale polyester geogrid movement is used for treatment. Under normal circumstances, the polyester geogrid for sale needs to be arranged on the top of the roadbed and the step position of the new and old subgrade contact. Only in this way can the new subgrade be upgraded. The adhesion between the old subgrade and the old subgrade can make the new subgrade and the old subgrade quickly form a monolithic structure under the condition that the lateral displacement and the uneven settlement are continuously reduced.
(2) Processing of the combination of new and old roadbeds
Under normal circumstances, when the roadbed filling height is >3m, it is necessary to arrange the steel-plastic composite grille at a position 20cm away from the roadbed cap. During construction, it is necessary to ensure that the transverse ultimate tensile force value of the plastic-plastic wholesale polyester geogrid is controlled above 20kN/m, the longitudinal ultimate tensile force is controlled above 60kN/m, and the elongation is ≤5%.
In summary, in order to meet the increasing vehicle traffic requirements, it is necessary to broaden the construction of highways with high load operation. When the highway engineering is widened, there is a certain difference in the consolidation time of the new embankment and the old embankment. It is easy to cause uneven settlement of the subgrade so that the lateral and longitudinal cracks appear in the joint location of the new subgrade and the old subgrade. And there are cases of embankment landslides and instability. In order to avoid settlement problems and cracks, it is necessary to determine the corresponding polyester geogrid for sale construction parameters in combination with the actual conditions of the project, to standardize the high quality polyester geogrid construction process, to ensure that the highway engineering subgrade widening construction quality can meet the requirements, and to improve the polyester geogrid for sale construction. Economic benefits.