Analysis on Surface Settlement Caused by Twin Bore Parallel Tunnel Excavation of City Subway

2016 ◽  
Author(s):  
Special Issues Editor
Keyword(s):  
Surface Settlement ◽  
Tunnel Excavation ◽  
Parallel Tunnel

SURFACE SETTLEMENT INDUCED BY TUNNELING IN GREENFIELD CONDITION THROUGH PHYSICAL MODELLING

2015 ◽  
Vol 76 (2) ◽  
Author(s):  
Aminaton Marto ◽  
Mohamad Hafeezi Abdullah ◽  
Ahmad Mahir Makhtar ◽  
Houman Sohaei ◽  
Choy Soon Tan
Keyword(s):  
Relative Density ◽  
Physical Modelling ◽  
Diameter Ratio ◽  
Surface Settlement ◽  
Ground Movement ◽  
Outer Diameter ◽  
Tunnel Excavation ◽  
Tunneling Method ◽  
Relative Density Of Sand ◽  
Tunnel Shield

Geotechnical conditions such as tunnel dimensions, tunneling method and soil type are few factors influencing the ground movement or disturbance.  This paper presents the effect of tunnel cover to diameter ratio and relative density of sand on surface settlement induced by tunneling using physical modelling. The aluminum casing with outer diameter of 50 mm was used to model the tunnel shield. The size of the casing was 2 mm diameter larger than the tunnel lining. The tunnel excavation was done by pulling out the tunnel shield at constant speed with a mechanical pulley. The tested variables are cover to diameter ratio (1, 2 and 3) and relative density of sand (30%, 50% and 75%). The results demonstrated that the surface settlement decreased as the relative density increased. Also, as the relative density of sand increased, the overload factor at collapse increased. The surface settlement was at the highest when the cover to diameter ratio was 2.  It can be concluded that in greenfield condition, the relative density and cover to diameter ratio affect the surface settlement.

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.

GA-NN Monitoring Model and its Application on Surface Settlement

2012 ◽  
Vol 505 ◽  
pp. 453-457
Author(s):  
Tie Sheng Wang ◽  
Hai Yan Li ◽  
Bing Zhang ◽  
Kai Feng Ma
Keyword(s):  
Neural Network ◽  
Influence Factors ◽  
Surface Settlement ◽  
Shield Tunnel ◽  
Tunnel Excavation ◽  
Monitoring Model ◽  
Efficiency And Effectiveness ◽  
Genetic Neural Network ◽  
Set Up ◽  
Under Construction

Combining the advantages of basic genetic algorithm and neural network, analyze and set up GA & NN genetic neural network, explore and study the algorithm. The efficiency and effectiveness of this hybrid training has been significantly improved comparing with the single genetic evolution or BP training method, its versatility is better. The model is applied to predict the deformation of shield tunnel excavation. According to the effects of measured influence factors under construction, it can make the appropriate forecast to the surface settlement which is better than the conventional regression model. It shows that neural networks in the ground during tunneling shield analysis and prediction of settlement is practical and adaptable.

Impact and Safety Assessment of a Double-Tube Parallel Tunnel Excavation on Adjacent Pipelines

2014 ◽  
Vol 889-890 ◽  
pp. 1421-1424
Author(s):  
Dong Liang Guo ◽  
De Shen Zhao
Keyword(s):  
Numerical Simulation ◽  
Finite Element ◽  
Finite Difference ◽  
Safety Assessment ◽  
Construction Safety ◽  
Tunnel Excavation ◽  
Project Construction ◽  
Parallel Tunnel

The interaction of a double-tube parallel tunnel excavation will have a larger additional shearing action on the adjacent pipelines. This paper, taking 202 Section of Line 2 on Dalian Metro as the background, uses the finite difference software to establish 3-D finite element analysismodel to simulate the double-tube parallel tunnel excavation. Deformation of adjacent pipelines is analyzed specially by numerical simulation of tunnel excavation and also the safety of the pipelines is forecasted. The conclusions and advices are important to design and guide the actual project construction safety.

scholarly journals A Method for Calculating Soil Deformation Induced by Shielded Tunneling in Ground Stratum with Cavities

Symmetry ◽  
2021 ◽  
Vol 13 (6) ◽  
pp. 1048
Author(s):  
Yunliang Cui ◽  
Yongjie Qi ◽  
Zihan Dai ◽  
Gang Wei
Keyword(s):  
Three Dimensional ◽  
Deformation Mode ◽  
Calculation Model ◽  
Surface Settlement ◽  
Soil Deformation ◽  
Tunnel Excavation ◽  
Limit Value ◽  
Soil Settlement ◽  
Combined Action ◽  
Depth Of Burial

The existence of cavities in shallow ground strata is one of the important causes of urban road collapse under the disturbance of tunnel excavation. Thus, this paper discusses the convergent deformation mode of ellipsoidal cavities. To this end, the convergent deformation of a cavity and the overall displacement of a tunnel were comprehensively examined. A three-dimensional symmetrical calculation model of the soil deformation under the combined action of the tunnel and the cavity was also established. Moreover, three-dimensional formulas for calculating the soil deformation and the surface settlement of the upper part of the tunnel and the cavity were derived. The influence of the different positions of the cavity on the surface settlement of the upper part of the tunnel was also examined. Further, the change in the soil settlement with the direction of the tunnel excavation and the depth of burial of the cavity was analyzed. The results show that the calculated settlement curves are consistent with the ones reported in the related literature. The cavity can also aggravate the surface settlement and deformation of the soil caused by the tunnel excavation. When the cavity is directly above the tunnel, the surface settlement curve is symmetrically distributed. As the position of the cavity changes, the overall settlement curve shifts to the direction of the cavity, showing asymmetry. Additionally, along the x-axis direction of the shielded tunnel, the surface settlement gradually increases to a limit value with a decrease in x and slowly declines to zero as x rises. Finally, along the depth of burial of the cavity, the settlement of the soil continues to enlarge; also, the growth rate of the soil settlement continues to increase further at positions closer to the cavity and the tunnel until it reaches a critical maximum.

scholarly journals Disturbance Process of Sandy Gravel Stratum Caused by Shield Tunneling and Ground Settlement Analysis

2021 ◽  
Vol 9 ◽  
Author(s):  
Nie Qingke ◽  
Sun Guang ◽  
Gao Siyuan ◽  
Liu Hongtao ◽  
Zhou Lichao ◽  
...  
Keyword(s):  
Pore Pressure ◽  
Soil Layer ◽  
Earth Pressure ◽  
Surface Settlement ◽  
Urban Rail Transit ◽  
Shield Tunneling ◽  
Tunnel Excavation ◽  
Sandy Gravel ◽  
Working Surface ◽  
The Earth

This paper analyzed the earth pressure, pore pressure, and surface settlement of the Luoyang urban rail transit tunnel in a sandy gravel stratum (Henan Province, China) under different burial depths by using field measurement methods. The results showed that the earth pressure as well as pore pressure of the soil layer above the working surface increased sharply and reached their maximum values when the cutter head of the shield gradually crossed the working surface. During the completion of synchronous grouting, the earth pressure and pore pressure increased slightly; when shield tunneling passed through the working surface, the earth pressure is smaller than the original earth pressure due to the unloading effect. The surface settlement curve above the tunnel took on a “V” shape after the completion of the left-side tunnel excavation, conforming to the normal distribution pattern. The surface settlement curve above the two tunnels took on a “W” shape after the completion of the right-side tunnel excavation, which is in good agreement with the proposed theoretical calculations. The findings of this study can help for better understanding the control of safety risk during shield construction.

Estimation of the ground surface settlement induced by the tunnel excavation in Changchun, China

2021 ◽  
Author(s):  
Jian Lu ◽  
Jingjing Sun ◽  
Yang Shen ◽  
Wei Zheng ◽  
Aijun Yao ◽  
...  
Keyword(s):  
Ground Surface ◽  
Surface Settlement ◽  
Tunnel Excavation ◽  
Ground Surface Settlement

Study on In Situ Monitoring of the Surrounding Rock Pressure of the Shallow Large-Span Tunnel in the Tunnel Construction Process

2011 ◽  
Vol 413 ◽  
pp. 454-458
Author(s):  
Xin Zhi Li ◽  
Shu Cai Li ◽  
Ying Yong Li ◽  
Shu Chen Li
Keyword(s):  
Rock Pressure ◽  
Surrounding Rock ◽  
In Situ Monitoring ◽  
Tunnel Engineering ◽  
Tunnel Face ◽  
Tunnel Excavation ◽  
Large Span ◽  
Parallel Tunnel ◽  
Surrounding Rock Pressure

The surrounding rock pressure which was determined effectively through in-situ monitoring was the important parametric of the tunnel engineering design.According to in-situ monitoring of the surrounding rock pressure in the relied engineering . The adjustment and distribution characteristics of surrounding rock pressure of the shallow large-span tunnel with three-level seven-step parallel tunnel excavation was studied, the results showed that the arch and sides of the tunnel arch foot were the key parts which concentrated the surrounding rock pressure. The adjustment and distribution of surrounding rock pressure had not obvious relationships with tunnel face distance. Finally, the composite factors that impacted monitoring results of the surrounding rock pressure was analysed. The results had great significance on the development and perfection of the surrounding rock pressure theory in shallow large-span tunnel.

Analysis of the Ground Surface Settlement of Metro Tunnel by Using Peck Formula

2014 ◽  
Vol 1065-1069 ◽  
pp. 414-420
Author(s):  
Xiong Fei Yang ◽  
Hong Yuan ◽  
Jia Yu Wu ◽  
Hou Mei Zhang
Keyword(s):  
Surface Deformation ◽  
Ground Surface ◽  
Surface Subsidence ◽  
Central Point ◽  
Surface Settlement ◽  
Point Method ◽  
Linear Regression Method ◽  
Tunnel Excavation ◽  
Ground Surface Settlement ◽  
Ground Surface Subsidence

Based on the peck formula, this paper has analyzed measured data of ground surface subsidence, and get the regression curve of ground surface subsidence. Expression for degree of reliability of the maximum ground surface settlement is derived analytically by using central-point method. On the basis of a certain section of tunnel of Guangzhou subway constructed by mining excavation method, linear regression method can be effectively fitting the ground surface deformation data due to tunnel excavation. The central-point method provides a new way for reliability analysis of the ground surface settlement of shield construction.

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