scholarly journals EXPERIMENTAL AND NUMERICAL STUDIES ON THE INFLUENCE TO THE EARTH PRESSURE OF SIDE WALL AND SEISMICALLY ISOLATION EFFECT OF UNDER GROUND BOX-CULVERT BY INSTALLING SHEAR STRESS REDUCER ON THE TOP SLAB

2015 ◽  
Vol 71 (1) ◽  
pp. 14-28 ◽  
Author(s):  
Hiroshi SATO ◽  
Yoshitaka OHSHIMA ◽  
Naoya OHKAWA
Keyword(s):  
Shear Stress ◽  
Side Wall ◽  
Earth Pressure ◽  
Isolation Effect ◽  
Numerical Studies ◽  
The Earth ◽  
Box Culvert

scholarly journals Characterization of Underlying Twin Shield Tunnels Due to Foundation-Excavation Unloading in Soft Soils: An Experimental and Numerical Study

2021 ◽  
Vol 11 (22) ◽  
pp. 10938
Author(s):  
Xiaodong Cheng ◽  
Tianqiu Hong ◽  
Zhitang Lu ◽  
Xiaochun Cheng
Keyword(s):  
Numerical Study ◽  
Structural Response ◽  
Earth Pressure ◽  
Experimental Tests ◽  
Foundation Pit ◽  
Soft Soils ◽  
Numerical Studies ◽  
The Earth ◽  
Depth Ratio ◽  
Side Walls

Excavation near or above existing shield tunnels often results in adverse impacts on tunnel stability. To ensure the serviceability of existing tunnels, this paper presents experimental and numerical studies with reference to a foundation pit case history excavated above twin-tube shield tunnels in soft soils. The experimental tests were firstly applied to study the deformation characteristics and structural response of the shield tunnels. Thereafter, an extensive numerical investigation was performed to determine the influence of some factors such as cover-to-excavation depth ratio, length-to-depth ratio, and unloading ratio on tunnel displacement behaviors. It was demonstrated that the tunnel heaves as the excavation proceeds, and heaves and horizontal displacements reach their maximum values when the excavation is finished. The earth pressure around the tunnels is symmetrically distributed in a gourd shape, with a larger reduction at the tunnel crown and invert and a smaller reduction at tunnel side walls. Additionally, the earth pressure at the tunnel crown and invert changes more significantly than that at other parts. The tunnel moment increment is significantly affected by the tunnel excavation depth. The axial force at or near the side walls of the tunnel is the most sensitive to the unloading effect induced by the excavation activity.

Numerical Simulation on Vertical Earth Pressure Distribution for Culverts under High Fills

2012 ◽  
Vol 204-208 ◽  
pp. 577-580
Author(s):  
He Fan ◽  
Bao Kuan Ning ◽  
Lei Gong
Keyword(s):  
Numerical Simulation ◽  
Stress State ◽  
Pressure Distribution ◽  
Side Wall ◽  
Earth Pressure ◽  
Structure Type ◽  
Mountain Area ◽  
Arch Effect ◽  
Type Selection ◽  
Box Culvert

High fill culverts have been widely used in expressway in mountain area and problems of culverts frequently take place because of improper design including some earth-pressure calculated values conservatively or culvert type selection irrationally. FEM numerical simulation was carried out to investigate the stress state of the culvert fill. The effect of four influences on the stress state of high-filled culvert is discussed. The research results show that culvert structure type influences earth pressure distribution that arch culvert is different to slab and box culvert. Earth pressure values when boundary slope is 1:0.35 are all larger than slope 1:0. Due to arch effect and stress distributed secondly, nonlinear increased amplitude of earth pressure is reduced with fill heightening. Earth pressure of culvert top and side decreased along with culvert side wall thickness increment. The research can give some references on the design correctly.

Coordinated optimization control of shield machine based on dynamic fuzzy neural network direct inverse control

2020 ◽  
pp. 014233122098027
Author(s):  
Xuanyu Liu ◽  
Wentao Wang ◽  
Yudong Wang ◽  
Cheng Shao ◽  
Qiumei Cong
Keyword(s):  
Fuzzy Neural Network ◽  
Control Method ◽  
Earth Pressure ◽  
Screw Conveyor ◽  
Inverse Control ◽  
The Earth ◽  
Coordinated Optimization ◽  
Optimization Control ◽  
Fuzzy Neural ◽  
Shield Machine

During shield machine tunneling, the earth pressure in the sealed cabin must be kept balanced to ensure construction safety. As there is a strong nonlinear coupling relationship among the tunneling parameters, it is difficult to control the balance between the amount of soil entered and the amount discharged in the sealed cabin. So, the control effect of excavation face stability is poor. For this purpose, a coordinated optimization control method of shield machine based on dynamic fuzzy neural network (D-FNN) direct inverse control is proposed. The cutter head torque, advance speed, thrust, screw conveyor speed and earth pressure difference in the sealed cabin are selected as inputs, and the D-FNN control model of the control parameters is established, whose output are screw conveyor speed and advance speed at the next moment. The error reduction rate method is introduced to trim and identify the network structure to optimize the control model. On this basis, an optimal control system for earth pressure balance (EPB) of shield machine is established based on the direct inverse control method. The simulation results show that the method can optimize the control parameters coordinately according to the changes of the construction environment, effectively reduce the earth pressure fluctuations during shield tunneling, and can better control the stability of the excavation surface.

Earth pressures exerted on an induced trench cast-in-place double-cell rectangular box culvert

2012 ◽  
Vol 49 (11) ◽  
pp. 1267-1284 ◽  
Author(s):  
Olajide Samuel Oshati ◽  
Arun J. Valsangkar ◽  
Allison B. Schriver
Keyword(s):  
Earth Pressure ◽  
Test Results ◽  
Overburden Pressure ◽  
Centrifuge Testing ◽  
Geotechnical Centrifuge ◽  
Drag Forces ◽  
Field Instrumentation ◽  
Earth Pressures ◽  
Box Culvert ◽  
Base Contact

Earth pressure data from the field instrumentation of a cast-in-place reinforced rectangular box culvert are presented in this paper. The instrumented culvert is a 2.60 m by 3.60 m double-cell reinforced cast-in-place rectangular box buried under 25.10 m of fill constructed using the induced trench installation (ITI) method. The average earth pressure measured across the roof was 0.42 times the overburden pressure, and an average of 0.52 times the overburden pressure was measured at mid-height of the culvert on the sidewalls. Base contact pressure under the rectangular box culvert was also measured, providing field-based data demonstrating increased base pressure resulting from downward drag forces developed along the sidewalls of the box culvert. An average increase of 25% from the measured vertical earth pressures on the roof plus the culvert dead load (DL) pressure was calculated at the culvert base. A model culvert was also tested in a geotechnical centrifuge to obtain data on earth pressures at the top, sides, and base of the culvert. The data from the centrifuge testing were compared with the prototype structure, and the centrifuge test results agreed closely with the measured field prototype pressures, in spite of the fact that full similitude was not attempted in centrifuge testing.

The earth pressure behind full-height integral abutments

2005 ◽  
Vol 90 (6) ◽  
pp. 55-58 ◽  
Author(s):  
Ming Xu ◽  
Alan G. Bloodworth
Keyword(s):  
Earth Pressure ◽  
The Earth ◽  
Integral Abutments ◽  
Full Height

Experimental Study on Earth Pressure of Corrugated Steel Culvert under High Fill Embankment

2013 ◽  
Vol 405-408 ◽  
pp. 1815-1819
Author(s):  
Wen Sheng Yu ◽  
Zhu Long Li ◽  
Xiao Ru Xie ◽  
Li Yuan Guo
Keyword(s):  
Mechanical Property ◽  
Experimental Study ◽  
Reinforced Concrete ◽  
Concrete Slab ◽  
Earth Pressure ◽  
Reinforced Concrete Slab ◽  
The Earth ◽  
Filling Height ◽  
Test Points ◽  
Better Than

To analyze the earth pressure of corrugated steel culvert under high fill embankment, a field test was taken and the change law was got with the filling height increasing, the force state when geotechnical grilles were laid on the top of corrugated steel culvert was compared to that of reinforced concrete slab culvert. Results show that the pressure on the top of corrugated steel culvert is smaller than that on the external in same level when test points are near to culvert, the values of test points above and below geotechnical grilles are close, and the pressure of corrugated steel culvert is smaller than that of reinforced concrete slab culvert when filling height is above 7.3 m. So analysis indicates corrugated steel culvert spreads the upper load better, the geotechnical grille can reduce the pressure effectively through earth pressure redistribution, and the mechanical property of corrugated steel culvert is better than reinforced concrete slab culvert under high fill embankment.

Predicting the Earth Pressure on Integral Bridge Abutments

2012 ◽  
Vol 17 (2) ◽  
pp. 371-381 ◽  
Author(s):  
Alan G. Bloodworth ◽  
Ming Xu ◽  
James R. Banks ◽  
Chris R. I. Clayton
Keyword(s):  
Earth Pressure ◽  
Bridge Abutments ◽  
Integral Bridge ◽  
The Earth
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