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.

The Finite Element Analysis of Shield Disk Cutter Based on Different Working Conditions

2012 ◽  
Vol 271-272 ◽  
pp. 1473-1477
Author(s):  
Qing Liang Zeng ◽  
Zhe Cui ◽  
Jun Wang ◽  
Yi Ran Wang ◽  
Hu Meng
Keyword(s):  
Finite Element ◽  
Three Dimensional ◽  
Calculation Model ◽  
Structure Design ◽  
Three Dimensional Model ◽  
Element Analysis ◽  
Tunnel Excavation ◽  
Geological Conditions ◽  
City Construction ◽  
Shield Machine

The shield machine is a large complete sets of equipment used for underground tunnel excavation in the city construction,it has been widely used in the tunnel excavation. Cutter is one of the key components of shield machine. Different geological conditions and badly application environment make the cutter stress complex. German Herrenknecht S749 shield cutter as an example, using PRO/E software to establish the three-dimensional model, ANSYS Workbench module establishes the cutter corresponding finite element calculation model, the force characteristics of the cutter in working process were analyzed, obtained the cutter`s stress strain distribution. The research results can provide basic data for the wheel structure design and construction maintenance.

scholarly journals Study on Surface Grouting Reinforcement Effect of Small Clear Distance Tunnel in Soil-rock Composite Stratum

2021 ◽  
Vol 276 ◽  
pp. 01004
Author(s):  
Lu-qiang Peng ◽  
Shi-hai Chen
Keyword(s):  
Elastic Modulus ◽  
Numerical Calculation ◽  
Calculation Model ◽  
Surface Settlement ◽  
Reinforcement Effect ◽  
Tunnel Excavation ◽  
Absolute Value ◽  
Calculation Results ◽  
Clear Distance ◽  
Grouting Reinforcement

Based on the Yingxiongshan tunnel project in Jinan, a numerical calculation model of tunnel excavation considering the surface grouting reinforcement effect of soil-rock composite stratum is established, and the effects of elastic modulus and grouting width of grouting reinforcement zone on tunnel stability are studied. and the research results are applied to the supporting project to verify the rationality of the numerical calculation results. The results show that grouting reinforcement can effectively control the deformation of surrounding rock and supporting structure, and the absolute value of surface settlement is negatively correlated with grouting width and elastic modulus. The surface settlement value is not sensitive to the change of the width of grouting reinforcement zone, but is sensitive to the change of elastic modulus.

Study of dynamic pressure on the packer for deep-water perforation

Open Physics ◽  
2021 ◽  
Vol 19 (1) ◽  
pp. 215-223
Author(s):  
Hao Huang ◽  
Qiao Deng ◽  
Hui Zhang
Keyword(s):  
Deep Water ◽  
Peak Pressure ◽  
Orthogonal Design ◽  
Dynamic Pressure ◽  
Three Dimensional ◽  
Calculation Model ◽  
Well Testing ◽  
Technical Problems ◽  
Wellbore Pressure ◽  
Three Dimensional Finite Element

Abstract The packer is one of the most important tools in deep-water perforation combined well testing, and its safety directly determines the success of perforation test operations. The study of dynamic perforating pressure on the packer is one of the key technical problems in the production of deep-water wells. However, there are few studies on the safety of packers with shock loads. In this article, the three-dimensional finite element models of downhole perforation have been established, and a series of numerical simulations are carried out by using orthogonal design. The relationship between the perforating peak pressure on the packer with the factors such as perforating charge quantity, wellbore pressure, perforating explosion volume, formation pressure, and elastic modulus is established. Meanwhile, the database is established based on the results of numerical simulation, and the calculation model of peak pressure on the packer during perforating is obtained by considering the reflection and transmission of shock waves on the packer. The results of this study have been applied in the field case of deep-water well, and the safety optimization program for deep-water downhole perforation safety has been put forward. This study provides important theoretical guidance for the safety of the packer during deep-water perforating.

Influencing analysis of different baffle factors on oil liquid sloshing in automobile fuel tank

2020 ◽  
Vol 234 (13) ◽  
pp. 3180-3193
Author(s):  
Enhui Zhang ◽  
Wenyan Zhu ◽  
Lihe Wang
Keyword(s):  
Three Dimensional ◽  
Fuel Tank ◽  
Liquid Sloshing ◽  
Inertia Force ◽  
Dimensional Finite Element ◽  
Combined Action ◽  
Adverse Influence ◽  
Three Dimensional Finite Element ◽  
Influence Degree ◽  
Sloshing Pressure

Oil liquid sloshing is a common phenomenon in automobile fuel tank under variable working conditions. Installing baffles in automobile fuel tank is the most effective way to suppress adverse influence caused by oil liquid sloshing. Different types of three-dimensional finite element models filling oil liquid are created, meshed, and simulated. The reliability of simulation results is verified by test. The concept of time–area value is proposed in this work. In order to explore the influence of different baffle factors on oil liquid sloshing, six factors are studied. Six kinds of influencing factors are height, structure, shape, spacing, number, and placement of baffles. The sloshing pressure and time–area value are the core parameters for evaluating the influence degree. Some results could be obtained by comparing the parameters of oil liquid sloshing under the same condition. High baffles and baffles with small spacing have obvious attenuation influence on the pressure of oil liquid sloshing. Low baffles, double baffles, parallel baffles, and the combined action of inertia force and gravity are more beneficial to the reduction of time–area value. Time–area value is the largest and the smallest in fuel tank with intersection baffles and low baffles, respectively.

Simulation on Torpedo Unsteady Hydrodynamic with the Movement in the Longitudinal Plane

2013 ◽  
Vol 791-793 ◽  
pp. 1073-1076
Author(s):  
Ming Yang ◽  
Shi Ping Zhao ◽  
Han Ping Wang ◽  
Lin Peng Wang ◽  
Shao Zhu Wang
Keyword(s):  
Three Dimensional ◽  
Engineering Application ◽  
Calculation Model ◽  
Trajectory Design ◽  
Design Calculation ◽  
Variable Speed ◽  
Accurate Calculation ◽  
Longitudinal Plane ◽  
Submerged Body ◽  
Mesh Method

The unsteady hydrodynamic accurate calculation is the premise of submerged body trajectory design and maneuverability design. Calculation model of submerged body unsteady hydrodynamic with the movement in the longitudinal plane was established, which based on unsteady three-dimensional incompressible fluid dynamics theory. Variable speed translational and variable angular velocity of the pitching motion in the longitudinal plane of submerged body was achieved by dynamic mesh method. The unsteady hydrodynamic could be obtained by model under the premise of good quality grid by the results. Modeling methods can learn from other similar problems, which has engineering application value.

Influence of shape of impactormade from high-strength steel on its fracture at high deformation rates

2021 ◽  
pp. 44-51
Author(s):  
P.A. Radchenko ◽  
◽  
S.P. Batuev ◽  
A.V. Radchenko ◽  
◽  
...  
Keyword(s):  
Finite Element Method ◽  
Fracture Criterion ◽  
Three Dimensional ◽  
High Strength ◽  
Head Part ◽  
The Finite Element Method ◽  
Plastic Deformations ◽  
High Deformation ◽  
Limit Value ◽  
Interaction Velocity

The fracture of high-strength impactor in interaction with a steel barrier is investigated. Three typesof head parts of the impactor are considered: flat, hemispherical and ogival. Normal and oblique interactions with velocities of 700 and 1000 m/s are investigated. Modeling is carried out by the finite element method in a three-dimensional formulation using the author's software EFES 2.0.The limit value of intensity of plastic deformations is used as a fracture criterion. The influence of the striker head part shape, interaction velocity, interaction angle on the fracture of the impactor and the barrier has been investigated. Conditions under which the striker ricochets were defined.

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.

Analysis of Surface Subsidence Rule of the Shallow Subway Tunnel Construction

2013 ◽  
Vol 671-674 ◽  
pp. 1081-1086 ◽  
Author(s):  
Fei Fei Wang ◽  
Hui Ren Bai ◽  
Jing Jing Li
Keyword(s):  
Ground Surface ◽  
Calculation Model ◽  
Surface Subsidence ◽  
Surface Settlement ◽  
Tunnel Construction ◽  
Maximum Point ◽  
Subway Tunnel ◽  
Monitoring Frequency ◽  
Ground Surface Settlement ◽  
Value Range

In order to study the Dalian Metro section 202(Cujin Road station-Chunguang Street station, which is shallowly buried and covered with plain fill)’s ground surface settlement, the monitoring measuring station was built during the construction. After 3 months’ measuring by precision level,the data shows that the maximum point is in the center line of the tunnel of the upper part. The settlement is about 25.66-31.82mm. This paper put forward the concept of the distance span ratio β, β effective value range was - 4 <β< 4,Surface subsidence is closely related with β, Severe surface subsidence stage is -2 <β< 2, Occupy whole deformation is 67.5-77.6%,settlement rate about 0.84-0.93mm/d, so should strengthen the monitoring frequency, Suggest increases site tour. Field test results and the ground surface settlement calculation model winkle are identical with each other; the monitoring results have important guiding significance and reference for Dalian subway and the similar shallow depth excavation tunnel construction.

Study on the Method of Construction of Large Section Tunnel Crossing the Ancient Great Wall

2012 ◽  
Vol 226-228 ◽  
pp. 1504-1508
Author(s):  
Ai Bing Jin ◽  
Long Fu Li ◽  
Fu Gen Deng ◽  
Min Zhe Zhang
Keyword(s):  
High Efficiency ◽  
Surface Deformation ◽  
Ground Deformation ◽  
Three Dimensional ◽  
Horizontal Displacement ◽  
Tunnel Excavation ◽  
Construction Scheme ◽  
Construction Experience ◽  
Strata Deformation ◽  
Great Wall

While the tunnel crossing the ancient Great Wall, we must take effective measures to control ground deformation, prevent ground deformation is too large, destroying the heritage. In order to study the effects of tunnel excavation types on strata deformation, a three-dimensional computational model is built to simulate surface settlement and horizontal displacement by three different excavation types which are both-side heading method, CRD method, and hole pile method. Following comparative analysis, in line with the realistic program is recommended. The results show that both-side heading method can better control the surface deformation, and has a high efficiency of construction, which was selected as the construction scheme of tunnel crossing the ancient great wall. The results of this study are expected to provide construction experience to the works of a similar background.

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