Study on safety optimization of embedding ratio of sand gravel deep foundation pit

doi:10.16265/j.cnki.issn 1003-3033.2021.01.018

Abstract

Abstract: In order to guide economic design and safe construction of deep foundation pit support structure in sandy gravel stratum, an optimization method of embedded depth (ratio of embedment) for supporting structure was put forward based on multiple safety evaluation indexes.with Luoyang Metro as an example Considering special properties of sandy cobble stratum which required construction of deep foundation pit to meet certain requirements of deformation and safety factor, surface settlement, stability of supporting structure, safety against uplift and safety against underground water gushing were analyzed, and selection range of embedding ratio was optimized based on limited displacement and safety factor. The results show that due to difference of groundwater level and exposed depth of pebble layer, Luoyang sandy cobble stratum can be divided into two types, and optimal embedding ratio ranges of type I (medium groundwater level and shallow exposed sand gravel) and type II (low groundwater level and deep exposed sand gravel) of deep foundation pit are 0.28 ～ 0.52 and 0.2 ～ 0.44, respectively.

Key words: sandy gravel, ratio of embedment, settlement, groundwater level, safety and stability

CLC Number:

X948

FENG Zhentu, LI Da. Study on safety optimization of embedding ratio of sand gravel deep foundation pit[J]. China Safety Science Journal, 2021, 31(1): 125-131.

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