scholarly journals Numerical Simulation on the Whole Sinking Process of Open Caisson with an Improved SPH Method

2021 ◽  
Vol 2021 ◽  
pp. 1-9
Author(s):  
Jiahe Zhang
Keyword(s):  
Pore Water Pressure ◽  
Water Pressure ◽  
Dynamic Change ◽  
Soil Pressure ◽  
Shield Tunneling ◽  
Material Interfaces ◽  
Engineering Problems ◽  
Domain Truncation ◽  
Particle Hydrodynamics ◽  
Sph Simulation

The phenomena of dynamic change in the material interfaces and mechanical properties are often involved in the caisson construction. Using conventional methods to simulate these phenomena is quite difficult due to the extremely large deformation. In this study, we proposed an improved soil-water-caisson interaction algorithm with the method of smoothed-particle hydrodynamics (SPH). This algorithm dealt with the support domain truncation of the particles near the blade and applied δ − SPH to avoid the pressure fluctuation. Meanwhile, the application of dynamic particles birth and death method could simulate the whole sinking process of an open caisson with underwater soil excavation. According to the comparison between SPH simulation and centrifuge test, the distribution of sidewall effective soil pressure was consistent, which indicated promising applicability of the algorithm. It should be noted that the considerable excess pore water pressure appeared in the surrounding soil under the blade. With the dissipation of the pressure over time, the effective soil stress increased correspondingly, and it would lead to the increasing difficulty of the sinking process. Therefore, the caisson should be avoided to stop for a long time during the sinking process or it would cause the stagnation of sinking. This algorithm could simulate engineering problems involving underwater construction effectively and provide theoretical and technical support for underwater excavation, shield tunneling, and other engineering problems.

In Situ Study on Soil Disturbance Induced by Shield Tunneling in Tianjin

2013 ◽  
Vol 368-370 ◽  
pp. 1674-1677
Author(s):  
Yong Hua Cao ◽  
Xiao Qiang Kou
Keyword(s):  
Pore Water ◽  
Pore Water Pressure ◽  
Water Pressure ◽  
Soil Disturbance ◽  
Ground Settlement ◽  
Soil Pressure ◽  
Shield Tunneling ◽  
Tunnel Face ◽  
Tunneling Process

In urban environment, the soil disturbance induced by shield tunneling can be sensitive because it can cause deformation of the ground and damage the near structure. To study this disturbance in the construction process of Tianjin metro line No.3, in-situ monitoring of pore water pressure, soil pressure and ground settlement were conducted. The pore water pressure was monitored for the soil around the tunnel. The soil pressure was monitored for the soil around the tunnel and on the tunnel face. It was revealed that the pore water pressure and soil pressure changed twice in the tunneling process and these changes were induced by cutting face and grouting at the shield tail. The soil pressure on the tunnel face reached its maximal value when the distance between the cutting face and the sensor elements was around the diameter of the tunnel. Ground settlement developed in the tunneling process. The shape of ultimate settlement trough is closed to the one obtained by Pecks method.

The Test Study to the Changes of Excess Pore Water Pressure during Precast Pile Construction

2012 ◽  
Vol 193-194 ◽  
pp. 1010-1013
Author(s):  
Shu Qing Zhao
Keyword(s):  
Pore Water ◽  
Clayey Soil ◽  
Pore Water Pressure ◽  
Water Pressure ◽  
Excess Pore Pressure ◽  
Soil Pressure ◽  
Excess Pore Water Pressure ◽  
Test Study ◽  
Excess Pore

The construct to precast pile in thick clayey soil can cause the accumulation of excess pore water pressure. The high excess pore pressure can make soil, buildings and pipes surrounded have large deflection, even make them injured. Combining with actual projects, this paper presents an in-situ model test on the changes of excess pore water pressure caused by precast pile construct. It is found that the radius of influence range for single pile driven is about 15m，the excess pore water pressure can reach or even exceed the above effective soil pressure, and there are two relatively stable stages.

scholarly journals Laboratory study on response of underwater cohesive sediment to columnar vibration source

2018 ◽  
Vol 54 (3) ◽  
pp. 193-202
Author(s):  
Peng Zhao ◽  
Feier Chen ◽  
Guoliang Yu
Keyword(s):  
Pressure Distribution ◽  
Experimental Observation ◽  
Pore Water ◽  
Pore Water Pressure ◽  
Water Pressure ◽  
Near Field ◽  
Mechanical Vibration ◽  
Cohesive Sediment ◽  
Vibration Source ◽  
Soil Pressure

Abstract This paper investigates the responses of cohesive sediment to mechanical vibration by experimental observation, containing: (1) the dynamic soil pressure, dynamic pore water pressure and dynamic acceleration to the vibration source; (2) the soil pressure distribution in the near field centered in an artificial columnar vibration source. Under the mechanical vibration with a frequency of 200 Hz and an amplitude of 1.15 mm, the dynamic soil pressure, dynamic pore water pressure and dynamic acceleration of underwater viscous sediment were measured in the sediment of four different depositing conditions. Results of the dynamic soil pressure, dynamic pore water pressure and dynamic acceleration of underwater viscous sediment in the near field responding to artificial vibration source are exhibited and discussed. It is found that, excited by the sinusoidal vibrator, the soil pressure presents a response of statistical sinusoidal fluctuation with the same frequency to the vibration source. In the sediment of lower initial yield stresses, the soil pressure distribution distinctly tends to firstly increase and then decrease with distance. The amplitude of the soil pressure is attenuated exponentially with distance.

Analysis on Surface Displacement Caused by Groundwater Seepage of Shield-Tunneling

2012 ◽  
Vol 170-173 ◽  
pp. 1740-1743
Author(s):  
Hai Xia Sun ◽  
Hai Jun Sang ◽  
Hai Yu Wu
Keyword(s):  
Pore Water Pressure ◽  
Water Pressure ◽  
Surface Displacement ◽  
Tunnel Engineering ◽  
Shield Tunneling ◽  
Seepage Field ◽  
Simulation Data ◽  
Groundwater Seepage ◽  
Set Up ◽  
Pressure Changes

Seepage is one of the unfavorable factors inducing construction accident. It is essential to analyze the influence to the displacement from seepage by the variety of the parameter of seepage. Set up simulation model by software Abaqus. This text studied the law on the displacement of groundwater during construction considering the influence of groundwater seepage, and contrasted the simulation data with groundwater and without groundwater. The pore water pressure changes because of the influence to seepage field from excavation. the displacement curves head for the same on different porosity. The settlement increase and the swell decrease with the addition of porosity. It is obvious that the displacement with groundwater is lager than without groundwater. A suggestion is made that the tunnel engineering should be designed with considering the influence of groundwater.

scholarly journals An Experimental Study on Dynamic Model Groove Under Shock Excitation

2019 ◽  
Vol 13 (1) ◽  
pp. 229-237
Author(s):  
Changmin Yang ◽  
Tongfei Hou ◽  
Bing Cui ◽  
Jiaqi Lou
Keyword(s):  
Dynamic Model ◽  
Control Method ◽  
Pore Water Pressure ◽  
Water Pressure ◽  
Single Point ◽  
Soft Clay ◽  
Traffic Load ◽  
Loading Frequency ◽  
Soil Pressure ◽  
Shock Excitation

Introduction: Variation laws of dynamic response and settlement deformation at different depths of soil roadbed were investigated and summarized in this study through a simulation test with a dynamic model groove in soft clay foundation of low road embankment. Materials and Methods: In this test, the traffic load was simulated by single-point and double-point shock excitation. Besides, loading frequency, intensity and duration were adjusted by a single variable control method. Research results show that peak values of soil pressure and pore water pressure decrease with the increase of buried depth, but they are unrelated to loading intensity and frequency. Conclusion: Nevertheless, settlement deformation does not increase linearly with the increase of frequency or time difference. The accumulative settlement at a depth varies as the loading time increases.

Groundwater Seepage Rule Simulation of Horse River Based on MIDAS/GTS

2012 ◽  
Vol 170-173 ◽  
pp. 3715-3719
Author(s):  
Bo Liu ◽  
Yong Tao Gao ◽  
Ai Bing Jin ◽  
Fu Gen Deng ◽  
Min Zhe Zhang
Keyword(s):  
Pore Water Pressure ◽  
Water Pressure ◽  
Dynamic Change ◽  
Element Model ◽  
Seepage Water ◽  
Reinforcement Scheme ◽  
Groundwater Seepage ◽  
Water Head ◽  
Total Head ◽  
Seepage Law

In order to understand more clearly the law of groundwater seepage, recharge, excretion and dynamic change of groundwater level in the Horse River of Xishimen Iron Mine, it makes full use of MIDAS/GTS to build seepage model of settlement zone in Horse River, and by the analysis of changes of total head and the pore water pressure of the model ,we can study Horse River seepage law in the influence of mining , and track and survey the actual project. The results show that, the finite element model with the actual engineering seepage water head, pore pressure are compared, so as to provide the basis for the selection of Horse River seepage reinforcement scheme.

Soil–Water-Structure Interaction Algorithm in Smoothed Particle Hydrodynamics (SPH) with Application to Deep-Penetrating Problems

2019 ◽  
Vol 17 (03) ◽  
pp. 1850135 ◽  
Author(s):  
Hao Wu ◽  
Jian Wang ◽  
Chun Wang ◽  
Jian Hua Wang
Keyword(s):  
Soil Water ◽  
Pore Water ◽  
Smoothed Particle Hydrodynamics ◽  
Pore Water Pressure ◽  
Water Pressure ◽  
Water Structure ◽  
Viscous Drag ◽  
Structure Interaction ◽  
Particle Hydrodynamics ◽  
Smoothed Particle

A fully coupled soil–water-structure interaction algorithm was presented in the framework of smoothed particle hydrodynamics (SPH). In this algorithm, soil–water interaction was simulated based on the two-phase mixture theory. Each phase of the mixture occupies part of the macroscopic mixture and satisfies its own conservation equations of mass and momentum. The Drucker–Prager model with nonassociated plastic flow rule was used to describe the constitutive behavior of soil. The water was treated as Newtonian fluid. Interaction between soil and water was modeled by the pore water pressure and the viscous drag force. The structure was considered as rigid and the interaction with soil/water was modeled by the frictional sliding contact algorithm. With this algorithm, it is possible to investigate pore water pressure, the effective stress and deformation of the soil undergoing large deformation. Moreover, the effect of the temporal and spatial evolution of soil porosity was taken into consideration. This study first examined the proposed algorithm for a U-tube seepage problem and a two-dimensional consolidation problem. Afterwards, the continuous deep penetrating process of the spudcan, which involved large soil deformation and complex soil–water-structure interaction, was simulated under axisymmetric conditions. The comparison with previous research indicates the robustness and applicability of the proposed algorithm. Furthermore, the proposed approach could be a potentially efficient tool helping to reveal the mechanism of soil failure in geotechnical, costal and ocean engineering.

In Situ Test on Effective Stress Principle for Ultra Soft Soil

2013 ◽  
Vol 291-294 ◽  
pp. 2641-2644
Author(s):  
Zhang Ming Li ◽  
Wen Xiu Zeng
Keyword(s):  
Effective Stress ◽  
Pore Water Pressure ◽  
Water Pressure ◽  
Soft Soil ◽  
Soil Pressure ◽  
Important Conclusion ◽  
Action Mode ◽  
Existing Problems

The effective stress principle for soil is inspected by examining the original concept and derivation of the principle from the perspective of the ultra-soft soil engineering applications; and the existing problems of the principle were discussed in accordance with the general methodology of mechanics, and relative engineering phenomena observed. The changes of pore water pressure and soil pressure with time were obtained based on series of long term in-situ test in a large ultra-soft ground treatment works directed by the first author; and then an important conclusion has acquired from the test, i.e. the effective stress principle is not a self-contained principle and it’s related to the medium constitutive characteristics and loading action mode.

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