Horizontal drainage system for vacuum preloading processing soft soil foundation

Abstract

Provided is a horizontal drainage system for vacuum preloading processing soft soil foundation. The horizontal drainage system for vacuum preloading processing soft soil foundation comprises drainage filter pipes, a drainage cushion layer and anti-break layers. The drainage cushion layer is formed by mixing coarse particles made from graded broken stones and graits with the diameter ranging from 10 mm to 30 mm and fine particles made from mineral powder and medium fine sands with the diameter ranging from 0.075 mm to 0.5 mm in a weight ratio ranging from 1:1 to 1:1.5. The silt content of material of the drainage cushion layer is ranging from 5%-10%. The filtration coefficient is bigger than 1*10<-4>m<3> / s. The thickness of the drainage cushion layer is ranging from 40 cm to 100 cm. The upper portion of the drainage cushion layer is provided with the anti-break layers which are made out of polymer geosynthetics. Compared with the traditional drainage system with a sand cushion layer, the horizontal drainage system has the equivalent drainage effect. The material of the drainage cushion layer is wide and easy to obtain. The project cost and the implement risk are lowered. Compared with the vacuum preload of a non-sand cushion layer, the vacuum preload has the advantages that the loss of the vacuum degree is low, the preload concretion effect is good, and the construction technology is simple.

Description

technical field [0001] The invention relates to a drainage system for treating soft soil foundations, in particular to a horizontal drainage system for vacuum preloading treatment of soft soil foundations. Background technique [0002] The soft clay layer of marine deposits is widely distributed in the newly reclamation area along the coast. This kind of soil has high water content, high compressibility, low strength and poor water permeability. Due to the low strength, the bearing capacity and stability of the foundation are often difficult to meet the engineering requirements, and the high compressibility and poor water permeability will cause considerable settlement and settlement difference under the long-term action of the upper load, and the settlement process lasts for a long time, which may affect the The normal use of the superstructure, therefore, such foundations usually need to take reinforcement measures, and the vacuum preloading method is one of the effective ...

AI Technical Summary

Problems solved by technology

However, the traditional horizontal drainage system highlights two problems: 1. The use of sand as the drainage cushion material source is tight and the cost is high

If the sand cushion is used in the horizontal drainage system, the thickness of the sand cushion is generally not less than 40cm, and it is preferably medium sand or coarse sand, and the permeability coefficient is not less than 5×10 -3 m 3 / s, for large-area soft foundation treatment projects, the amount of medium-coarse sand required is relatively large, but sand resources are in short supply in my country's muddy coastal areas, the contradiction between supply and demand is prominent, and the price and cost are high

2. Vacuum preloading without sand cushion is used, which makes the construction difficult and the loss of vacuum degree is large

Due to the low bearing capacity of the foundation in silty soft soil areas, construction machinery cannot directly enter the site for construction. Using the vacuum preloading technology without sand cushion, manual work is time-consuming and labor-intensive, and the labor cost is high; at the same time, the loss of vacuum degree increases, which reduces the preloading Consolidation effect

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