A construction method for shallow foundation pit dewatering for water-rich pebble layer

Abstract

The present invention proposes a shallow foundation pit dewatering construction method for water-rich pebble layers, which relates to the field of dewatering of pebble layer foundation pits, comprising the following steps: S1, construction preparation for dewatering wells; S2, drilling, and the drilling rig is in place Preset the location of the dewatering well to drill and run the well pipe; S3, install PVC pipe in the well pipe; S4, drill and inject grout in the pebble layer around the foundation pit; S5, detect the grouting effect in the pebble layer; S6, start the dewatering work, the The invention forms an anti-seepage curtain between two dewatering wells to guide groundwater into the dewatering radius of the dewatering well, which has the advantages of good dewatering effect and high dewatering efficiency, saves construction costs and shortens the construction period.

Description

technical field [0001] The invention relates to a construction method for dewatering a shallow foundation pit in a water-rich pebble layer. Background technique [0002] With the rapid development of my country's construction industry, the scale of construction continues to expand, and the geological conditions involved are becoming more diverse. At the same time, as people's requirements for the living environment gradually increase, residential buildings near rivers, rivers and their tributaries gradually rise. Due to the particularity of the geographical environment in the area of ​​rivers and their tributaries, the geological layers mostly form a structure of silt layer, pebble layer and mudstone layer from top to bottom. The large porosity of the pebble layer leads to its high water seepage and permeability. , and the groundwater near the river is relatively abundant, the groundwater is more likely to enter the foundation pit through the pebble layer during the constructi...

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Problems solved by technology

[0002] With the rapid development of my country's construction industry, the scale of construction continues to expand, and the geological conditions involved are becoming more diverse. Due to the particularity of the geographical environment in the area of ​​rivers and their tributaries, the geological layers mostly form a structure of silt layer, pebble layer and mudstone layer from top to bottom. The large porosity of the pebble layer leads to its high water seepage and water permeability. , and the groundwater near the river is relatively rich, and the groundwater is more likely to enter the foundation pit through the pebble layer during the construction process, which increases the workload of foundation pit dewatering, further affects the construction progress, and increases the related costs in the construction; at the same time, the pebble layer The overall stability is low, and it is more likely to collapse during the construction of the foundation pit, which affects the construction process and also poses a greater safety hazard

[0003] In the existing technology, in the precipitation of foundation pits in water-rich pebble layers, in order to enhance the precipitation effect, the method of intensively drilling holes around the foundation pit is often used. This method can improve the precipitation effect to a certain extent, but the intensive drilling method is in the While increasing the cost, it will also cause certain damage to the stability of the relatively loose pebble layer structure;

[0004] And the dewatering wells can only discharge groundwater within a certain range nearby. When the density of the dewatering wells is too high, the convergence speed of the groundwater is lower than the drainage speed of the dewatering wells. After multiple dewatering wells discharge the groundwater near the surrounding sides of the foundation pit, it will Stop working until the groundwater re-converges and start working again, and the intermittent working mode of the precipitation well during the drainage process is inefficient;

[0005] Due to the excessively large gaps in the pebble layer itself, even if the method of increasing the number of precipitation wells is used to drain the groundwater intensively during the drainage process, a considerable part of the groundwater will still enter the foundation pit through the gaps between the pebble layers between the precipitation wells. , during the construction of the foundation pit in the later period, the drainage work for the groundwater entering the foundation pit will be increased

[0006] In order to solve the water seepage problem of the pebble layer involved in the above scheme, some construction units will adopt the construction method of cast-in-place pile + water-stop curtain. This construction method is expensive and is mostly suitable for deep foundation pit construction. If it is applied to shallow foundation The pit construction will greatly exceed the original construction budget

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