Method for Determining Design Parameters of Deep Horizontal Water-stop Curtain in Foundation Pit in Highly Permeable Stratum

Abstract

The invention discloses a method for determining the design parameters of the deep horizontal water-stop curtain of foundation pits in strong water-permeable strata, and establishes a mechanical analysis model of the deep horizontal water-stop curtain; ", "contact failure" and "stiffness failure" and other four types of critical depths of failure modes; draw the critical depth h cr and thickness h 0 The curve relationship of the deep horizontal water-stop curtain is further compared with the critical depth of the deep horizontal water-stop curtain under four different "destruction modes", and then the maximum value of the four is selected as the design value of the critical depth of the deep horizontal water-stop curtain; The relationship curve between the critical depth of the curtain and the thickness of the horizontal water-stop curtain can be used to obtain the best design parameters of the deep horizontal water-stop curtain that meet the requirements of the safety factor. The design parameters obtained by the invention are more reasonable and reliable, which ensures the construction safety of deep foundation pits in highly permeable formations.

Description

technical field [0001] The invention relates to the field of underground engineering, in particular to a method for determining design parameters of a deep horizontal water-stop curtain for foundation pits in highly permeable strata. Background technique [0002] In recent years, with the vigorous development of urban underground space construction in my country, the construction of foundation pit projects has become more and more extensive, showing the characteristics of "large number, large scale, and deep depth". The groundwater levels in coastal (river) cities such as Shanghai, Guangzhou, Tianjin, Fuzhou, and Wuhan in China are generally high. During the excavation of deep foundation pits, precipitation is first required. However, the aquifer thickness of deep foundation pits in coastal cities is very large, and the relatively impermeable layer is buried relatively deep. If the traditional vertical water-stop curtain scheme with falling bottom is used for partition, the ...

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Problems solved by technology

[0003] After searching the existing technical literature, it is found that the reasonable range of the deep horizontal water-stop curtain has not been determined, and there are few related studies on the determination of the overall reinforcement depth and thickness. If the traditional earth pressure balance method and seepage force balance method are adopted The pit inrush calculation method ignores the anti-inrush effects of parameters such as the shear strength and stiffness of the deep horizontal water-stop curtain seepage barrier, so the results obtained are quite different from the field conditions. The mechanical performance parameters (shear strength, stiffness and permeability coefficient) of the water curtain have been greatly improved. Therefore, when analyzing the foundation pit inrush problem under the deep horizontal water-stop curtain, the influence of these mechanical parameters on it should be considered.

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