scholarly journals Maximum surface settlement induced by shallow tunneling in layered ground

2020 ◽  
pp. 55-60
Author(s):  
A Boustila ◽  
A Hafsaoui ◽  
M Fredj ◽  
S Yahyaoui
Keyword(s):  
Surface Settlement ◽  
Maximum Surface ◽  
Maximum Surface Settlement ◽  
Layered Ground

Surface Settlement Law Induced by Shield Tunnel Excavation Using Modified Gap Model

2012 ◽  
Vol 170-173 ◽  
pp. 1515-1519
Author(s):  
Wen Bo Li ◽  
Wen Pei Wang ◽  
Lian Jin Tao ◽  
Yin Tao Zhang
Keyword(s):  
Critical Value ◽  
Surface Settlement ◽  
Shield Tunnel ◽  
Gap Model ◽  
Tunnel Excavation ◽  
Maximum Settlement ◽  
Maximum Surface ◽  
Adjacent Buildings ◽  
Maximum Surface Settlement ◽  
Tunnel Depth

GAP model will be modified and programmed by FISH language, which can be used in FLAC2D programs. The modified GAP model is used to study the variation of surface settlement shape with depth, the variation of the maximum settlement value with depth, and the variation of settlement gradient with depth. The results show that: the settlement shape is narrow and deep with the conditions of shallow buried depth of tunnel; on the contrary, the settlement shape is wide and shallow; When the tunnel depth is less than the critical value, the tunnel depth and the maximum surface settlement is approximately linear; when the tunnel depth is greater than the critical value, the curve of maximum surface settlement value with depth becomes flat and with the increase of the tunnel, the surface settlement gradient gradually decreases and eventually tends to zero. It is more reasonable to assess the influence of tunnel excavation near adjacent buildings, using the maximum surface settlement and the settlement gradient as a control standard.

scholarly journals The effect of the additional load on the ground support on the settlement of the surrounding ground

2021 ◽  
Vol 272 ◽  
pp. 02015
Author(s):  
Dong Wang ◽  
Xu Zhang ◽  
Wenkai Zhang ◽  
Junpeng Liu ◽  
Zhengyue Shi ◽  
...  
Keyword(s):  
Numerical Simulation ◽  
Bottom Layer ◽  
Rate Of Change ◽  
Surface Settlement ◽  
Foundation Pit ◽  
Maximum Surface ◽  
Additional Load ◽  
Ground Support ◽  
Soil Settlement ◽  
Maximum Surface Settlement

Based on the existing engineering examples, this paper uses numerical simulation combined with the actual monitoring values on site to study the effect of the additional load on the support and the settlement of the surrounding ground, and the following conclusions are drawn: (1) When the enclosure structure is good, the settlement curve generally assumes a “spoon shape”. As the distance from the foundation pit increases, the surface settlement curve first increases and then decreases. The distance between the location of the maximum surface settlement and the foundation pit is generally half of the maximum excavation depth of the foundation pit. (2) The existence of additional load accelerates the rate of change of surface settlement, making the soil settlement from the excavation of the first layer of soil as a whole smaller than the unacted additional load to the excavation to the bottom layer as a whole larger than the unapplied load. (3) There will be a certain gap between the numerical simulation and the actual monitoring value. This gap will become larger and larger as the excavation of the foundation pit continues, but the law of change between the two is the same.

scholarly journals Membrane effect of geosynthetic reinforcement subjected to localized sinkholes

2018 ◽  
Vol 55 (9) ◽  
pp. 1334-1348 ◽  
Author(s):  
Shi-Jin Feng ◽  
Shu-Gang Ai ◽  
Hong-Xin Chen
Keyword(s):  
Surface Settlement ◽  
Preliminary Design ◽  
Vertical Deformation ◽  
Geosynthetic Reinforcement ◽  
Interface Friction ◽  
Maximum Surface ◽  
Membrane Effect ◽  
Supporting Soil ◽  
Scale Experiment ◽  
Maximum Surface Settlement

A membrane effect often occurs in geosynthetic-reinforced structures, where subsoil may have voids or sinkholes. An analytical model is proposed to estimate membrane effect of a geosynthetic reinforcement subjected to localized sinkholes. The upper interface friction in the subsided area and vertical deformation of supporting soil in the anchorage area are considered simultaneously. The maximum geosynthetic strain and maximum surface settlement, serving as key design points, can be determined. Based on the proposed method verified using a full-scale experiment, a parametric study is conducted. The results show that ignoring upper interface friction results in significant undervaluation of maximum geosynthetic strain, and ignoring vertical deformation of supporting soil leads to obvious undervaluation of maximum surface settlement. A practical design framework is also proposed and it is an applicable tool for preliminary design of geosynthetic-reinforced structures, especially for cases with soft ground.

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