scholarly journals Seepage Force on a Buried Submarine Pipeline Induced by a Solitary Wave

2020 ◽  
Vol 8 (5) ◽  
pp. 324
Author(s):  
Meng-Yu Lin ◽  
Li-Jie Wang
Keyword(s):  
Solitary Wave ◽  
Young’S Modulus ◽  
Permeability Coefficient ◽  
Pore Water Pressure ◽  
Young's Modulus ◽  
Water Pressure ◽  
Vertical Force ◽  
Submarine Pipeline ◽  
Seepage Force ◽  
Poroelastic Seabed

In this study, a finite element method was used to establish a two-dimensional numerical model to solve the problem of the Biot equation describing the poroelastic seabed, and to analyze the seepage force on a buried submarine pipeline under the propagation of a solitary wave. The model provides a solution to the displacement of the poroelastic seabed and the variation of the pore-water pressure. By means of numerical simulation, the effects of Young’s modulus and permeability coefficient of the soil on the pore-water pressure and seepage force are discussed. In the simulation of solitary waves passing through fully buried submarine pipelines, numerical results indicate that the smaller the permeability coefficient in dense sandy bed the greater the vertical force acting on the pipeline, and the smaller the permeability coefficient in loose sand bed the smaller the vertical force acting on the pipeline. In general, when the permeability coefficient is large, the smaller the Young’s modulus the more obvious the influence of the vertical force on the pipeline, and when the permeability coefficient is small, the larger the Young’s modulus the more obvious the influence of the vertical force on the pipeline.

scholarly journals Effect of Colluvial Soil Slope Fracture’s Anisotropy Characteristics on Rainwater Infiltration Process

2018 ◽  
Vol 2018 ◽  
pp. 1-11 ◽  
Author(s):  
Ling Zeng ◽  
Jie Liu ◽  
Jun-hui Zhang ◽  
Han-bing Bian ◽  
Wei-hua Lu
Keyword(s):  
Pore Water ◽  
Permeability Coefficient ◽  
Pore Water Pressure ◽  
Water Pressure ◽  
Positive Pressure ◽  
Saturated Zone ◽  
Infiltration Depth ◽  
Infiltration Process ◽  
Fracture Angle ◽  
Rainwater Infiltration

The SEEP/W module of finite element software GEO-slope is used to analyze the effects of fracture depth, permeability coefficient ratio, fracture angle, and fracture number on the rainwater infiltration process. Moreover, the effect of fracture seepage anisotropy on slope stability is discussed combining with unsaturated seepage theory. The results show that the pore water pressure in the fracture increases rapidly with the rainfall until it changes from negative pressure to positive pressure. The greater the fracture depth is, the greater the pore water pressure in the fracture is, and the greater the infiltration depth at the time of rainfall stopping is. When the permeability coefficient is greater than the rainfall intensity, the permeability coefficient ratio has a great influence on the infiltration process of rainwater. The smaller the fracture angle is, the greater the maximum pore water pressure is in the fracture depth range, and the greater the depth of the positive pore water pressure is. However, with the increase of fracture angle, the infiltration depth decreases, and the range of the surface saturation area of slope increases obviously. With the increase of fracture density, the saturated positive pressure region is connected to each other in the slope. The influence range and the degree of the rainwater on the seepage field are larger and larger. There is a power relation between the saturation area and the fracture number, and also the concentration distribution of long fractures directly forms the large-connected saturated zone and raises groundwater. The range of the saturated zone and variation law of the pore water pressure under fracture seepage are obtained, which provide a reference for the parameter partition assignment of slope stability analysis under fracture seepage.

Research on Influencing Factors of Drainage Performance in Engineering

2012 ◽  
Vol 212-213 ◽  
pp. 671-678
Author(s):  
Xu Shu Sun ◽  
Jian Lin Li ◽  
Xiao Liang Xu ◽  
Jian Rrong Li ◽  
Fei Liu
Keyword(s):  
Influencing Factors ◽  
Small Angle ◽  
Permeability Coefficient ◽  
Pore Water Pressure ◽  
Water Pressure ◽  
Soil Mass ◽  
Vertical Permeability ◽  
Horizontal Drainage ◽  
Drainage Hole ◽  
Better Than

In order to control the seepage and eliminate the adverse effects, influencing factors of drainage in engineering are discussed in this paper. The drainage holes are simulated by rod element to study the influence of drainage performance on angle and length. Compared the drainage performance of drainage galleries in different location, the optimal assembly is obtained. Meanwhile, drainage performance is analyzed by different permeability coefficient and anisotropy of rock and soil mass. The results show that: (1) Drainage flow of small angle and short drainage hole is close to big angle and long one, the small angle flows more than the big angle when increasing the same length. (2) Shallow drainage galleries can significantly drop the free surface and the deep one can greatly decrease the pore water pressure. Drainage galleries built at the upstream side and bottom, as the optimum assembly, can enormously change the seepage field. (3) For anisotropy materials, the horizontal drainage performance is better than vertical when Ky/Kx decreases. On the contrary, vertical is superior to the horizontal. Increasing vertical permeability coefficient is benefit to drainage.

Numerical Analysis of Characteristics of Moisture Migration in Soil Slope under Rainfall

2014 ◽  
Vol 501-504 ◽  
pp. 1927-1931
Author(s):  
Guang Ju Wen ◽  
Wen Jie Deng ◽  
Feng Wen
Keyword(s):  
Pore Water ◽  
Permeability Coefficient ◽  
Slope Failure ◽  
Pore Water Pressure ◽  
Soil Mechanics ◽  
Water Pressure ◽  
Point Of View ◽  
Moisture Migration ◽  
Unsaturated Soil Mechanics ◽  
Nonlinear Distribution

Based on the characteristics of slope failure induced by rainfall, from the point of view of moisture migration and combining unsaturated soil mechanics, the characteristics of moisture migration in slope under different rainfall intensities were analyzed by finite element method. The results reveal that under rainfall, the pore water pressure in slope is in layered distribution, and at the bottom of slope, the pore water pressure is the highest, the top is lower and the middle is the lowest. The volumetric water content is in nonlinear distribution and the degree of nonlinear in unsaturated area is higher than that of the saturated area. The permeability coefficient of soil rises with the increase of rainfall intensity, and when the soil is saturated, its permeability coefficient is saturate permeability coefficient.

scholarly journals Tunnel Behaviour Caused by Basement Excavation in Clay

Geofluids ◽  
2021 ◽  
Vol 2021 ◽  
pp. 1-11
Author(s):  
Huasheng Sun ◽  
Jihua Zhang ◽  
Guodong Zhao ◽  
Hao Wang
Keyword(s):  
Permeability Coefficient ◽  
Pore Water Pressure ◽  
Water Pressure ◽  
Three Dimensional ◽  
Soil Permeability ◽  
Foundation Pit ◽  
Nonlinear Constitutive Model ◽  
Tunnel Diameter ◽  
Consolidation Time ◽  
Diameter Change

Many researchers have investigated the effect of basement excavation on tunnel deformation. However, the influence of consolidation on the interaction of basement-tunnel-soil is rarely considered or systematically studied in clay. In this study, three-dimensional coupled-consolidation finite element analyses were conducted to investigate the effect of consolidation on the tunnel response to excavation. An advanced nonlinear constitutive model was adopted, and numerical parametric investigations were conducted to study the effect of the excavation depth, tunnel stiffness, soil permeability coefficient, and consolidation time on the tunnel response. The results revealed that the basement excavation led to stress release, which caused tunnel heave. Owing to the dissipation of excess negative pore water pressure, the tunnel heave further increased to become approximately twice as large compared with that observed when the foundation pit excavation had just been completed. As the consolidation time increased, the longitudinal tunnel heave and tunnel diameter change caused by the foundation pit excavation gradually increased, but the growth rate was slower down. When the consolidation time changed from 50 days to 150 days, the maximum tunnel heave at the crown and the maximum tunnel diameter change increased by 1.18 and 1.48 times, respectively. The soil’s permeability coefficient did not have a significant effect on the tunnel heave at the crown nor on the tunnel diameter change. The results obtained by this study are expected to be useful as an engineering reference for the analysis of soil structure problems in clay.

3-D FEM Seepage Simulation of Channel with Drain Pipes

2011 ◽  
Vol 137 ◽  
pp. 198-204
Author(s):  
Zong Kun Li ◽  
Yu Rong Huang ◽  
Jian You Wang ◽  
Qiang Zi
Keyword(s):  
Permeability Coefficient ◽  
Pore Water Pressure ◽  
Water Pressure ◽  
Water Transfer ◽  
Middle Line ◽  
Common Elements ◽  
High Permeability ◽  
Water Head ◽  
Inner Surface ◽  
North Water

In order to simulate the seepage field with drain pipes, the air element method is used in this paper. In this method, the pipe elements are regarded as a kind of material with high permeability coefficient and an equivalent hydraulic conductivity is assigned to them. Thus these pipe elements can be included in the conventional seepage calculation as other common elements. Moreover, the difficulty of giving water head boundary to the inner surface of pipes directly is avoided. According to the seepage calculation of the channel with large number of drain pipes in Huangyou part of the middle line in South-to-North water transfer project, the results show that, with drainage-piping, the pore water pressure in channel foundation is reduced significantly.

Numerical Simulation of Post-Construction Deformation Characteristics of Storage Oil Tank Ground

2013 ◽  
Vol 353-356 ◽  
pp. 593-596 ◽  
Author(s):  
Yan Mei Zhang ◽  
Xu Dong Zhang
Keyword(s):  
Permeability Coefficient ◽  
Pore Water Pressure ◽  
Ground Deformation ◽  
Water Pressure ◽  
Three Dimensional ◽  
Element Model ◽  
Additional Stress ◽  
Soil Parameters ◽  
Ground Settlement ◽  
Constrained Modulus

Ground soil was looked as porous medium, a three-dimensional finite element model of shell-liquid-foundation-ground was built, and the influence of soil parameters, filling liquid mode, and liquid height on the tank ground deformation was discussed. The research shows that the subsidence range caused by additional stress is the 0.3D range of the tank bottom edge outer; the influence of soil constrained modulus on settlement is remarkable, with constrained modulus decreasing, the tank ground settlement increases; with soil permeability coefficient decreasing, the tank ground settlement decreases; the ground settlement curve shape is decided by soil constrained modulus and permeability coefficient; the influence of filling liquid mode on the ground final settlement is very small ,but on the pore water pressure peak is remarkable.

scholarly journals Strengthening the Rigidity of Landslide Materials Measured by Seismic Interferometry

2021 ◽  
Vol 13 (14) ◽  
pp. 2834
Author(s):  
Keng-Hao Kang ◽  
Wei-An Chao ◽  
Che-Ming Yang ◽  
Ming-Chien Chung ◽  
Yu-Ting Kuo ◽  
...  
Keyword(s):  
Pore Water Pressure ◽  
Water Pressure ◽  
Recovery Process ◽  
Mechanistic Explanation ◽  
Seepage Water ◽  
Vertical Force ◽  
Water Tank ◽  
Rainy Period ◽  
Intense Precipitation ◽  
Stress Dependent

Landslides have caused extensive infrastructure damage and caused human fatalities for centuries. Intense precipitation and large earthquakes are considered to be two major landslide triggers, particularly in the case of catastrophic landslides. The most widely accepted mechanistic explanation for landslides is the effective-stress dependent shear strength reduction due to increases in pore water pressure. The Chashan landslide site, selected for the present study, has been intensively studied from geological, geophysical, geodetic, geotechnical, hydrological, and seismological perspectives. Our seismic monitoring of daily relative velocity changes (dv/v) indicated that landslide material decreases coincided with the first half of the rainy period and increased during the latter half of the rainy period. The geodetic surveys before and after the rainy period identified vertical subsidence without horizontal movement. The results from the multidisciplinary investigation enabled us to draw a conceptual model of the landslide recovery process induced by water loading. Where all sliding materials were stable (safety factor > 1.0), unconsolidated landslide colluvium and impermeable sliding surfaces trapped the seepage water to form a water tank, provided that compact forces were acting on the materials below the sliding boundary. The vertical force of compaction facilitates an increase in the cohesion and strength of landslide materials, thereby increasing the landslide materials’ stability. We demonstrated that the recovery process periodically occurs only under the combined conditions of prolonged and intense precipitation and the related stability conditions.

scholarly journals Comparative Analysis of Roadway Reinforcement Effects Based on Fluid-Solid Coupling in the Fractured Zone of Water-Rich Fault

2018 ◽  
Vol 2018 ◽  
pp. 1-14
Author(s):  
Jihua Zhang ◽  
Yun Dong ◽  
Yadong Chen ◽  
Yang Jiang ◽  
Huasheng Sun ◽  
...  
Keyword(s):  
Fault Zone ◽  
Permeability Coefficient ◽  
Pore Water Pressure ◽  
Water Pressure ◽  
Water Inrush ◽  
Surrounding Rock ◽  
Fractured Zone ◽  
Transient Electromagnetic ◽  
Working Face ◽  
Fissure Water

Water inrush is a common geological disaster during the roadway excavation process in the broken zone of water-rich faults. In this paper, the 15107 mining roadway built by Yuxing coal mine in such a fault zone was used as a case study to determine the water content of the surrounding rocks and a fault zone using the transient electromagnetic method (TEM). Also, the mechanics characteristics of such rocks in both saturated and unsaturated states were analyzed, a computational model for fluid-solid coupling in the water-rich fault fracture zone was established, and the permeability coefficient of the rocks under both shield support and bolt-grouting support was compared, along with analyzing the changes in pore pressure, fissure water velocity, and characteristics of deformation in the surrounding rocks. The numerical simulation results show that the fault range has an influence of about 20 m, which causes the forms of permeability coefficient to change like a hump. The permeability coefficient in the fractured zone is the largest, and the mutation rate at the fault plane is faster. Bolting not only reduces the permeability coefficient of the surrounding rock that is 1/10 of the beam support but also prevents the roof fissure water inrushing the roadway and the surrounding rock of the floor, while also causing the pore-water pressure to decrease, even reduce to zero, in front of the working face and floor. The flow velocity of the fissure water can be decreased by bolting, which can effectively control the deformation of the surrounding rock by 38.7%∼65% compared with the shield support. The practice results show that this method can effectively recover the cracks surrounding the mining roadway and stop gushing water. Concurrently, it successfully controls deformation of the surrounding rocks in the fault zone, thus ensuring stability of the roadway and facilitating safer mining production.

scholarly journals Experimental and Numerical Studies on Permeability Properties of Thermal Damaged Red Sandstone under Different Confining Pressures

Geofluids ◽  
2021 ◽  
Vol 2021 ◽  
pp. 1-13
Author(s):  
Zhenlong Zhao ◽  
Hongwen Jing ◽  
Guangping Fu ◽  
Qian Yin ◽  
Xinshuai Shi ◽  
...  
Keyword(s):  
Numerical Modeling ◽  
High Temperature ◽  
Pore Water ◽  
Permeability Coefficient ◽  
Pore Water Pressure ◽  
Water Pressure ◽  
Darcy's Law ◽  
Equivalent Permeability ◽  
Red Sandstone ◽  
Confining Pressures

The stability and safety of underground rock mass engineering are closely related to the permeability process of fluids and permeability properties of rocks. To reveal the flow behavior of fluid in thermal damaged rock, first, a rock seepage testing system was applied to study the permeability properties of red sandstone specimens after different high-temperature treatments from 200 to 800°C under different confining pressures of 10 to 30 MPa. Meanwhile, the microstructures of the red sandstone specimens were characterized by the mercury intrusion porosimetry (MIP) and scanning electron microscopy (SEM). Then, the permeability process of pore water pressure and the flow form of fluid also were investigated by the numerical modeling method. The results show that the permeability properties of red sandstone specimens after high-temperature exposure follow linear Darcy’s law, and the relation between confining pressures and equivalent permeability coefficient ( K 0   ) can be described by a power function. Besides, the phenomenon that microscopic structural deterioration is intensified with increasing temperature and the average pore size and porosity of the red sandstone specimens are both power functions is related to the equivalent permeability coefficient. Furthermore, the results of numerical modeling indicated that the flow field within the range affected by confining pressures gradually becomes stable and orderly from disorder, and flow lines of the fluid become smooth and straight, and perpendicular to the isosurface of pore water pressure as time goes by. Moreover, the nonlinear correlation between pore water pressure and seepage path length changes to a linear correlation, which is consistent with linear Darcy’s law.

Influence of Water Saturation on Dynamic Responses of a Partially Sealed Tunnel

2012 ◽  
Vol 204-208 ◽  
pp. 1510-1513
Author(s):  
Min Jie Wen ◽  
Zi Ping Su
Keyword(s):  
Pore Water ◽  
Permeability Coefficient ◽  
Water Saturation ◽  
Pore Water Pressure ◽  
Water Pressure ◽  
Great Influence ◽  
Dynamic Responses ◽  
Harmonic Load ◽  
Homogeneous Fluid ◽  
Influence Of Water

The mixture of water and gas is treated as a homogeneous fluid. Based on Boit’s theory, the influences of water saturation on the dynamic responses of a partially sealed tunnel are investigated in the frequency domain. By utilizing the continuous condition, the analytical solutions of the displacement, stress and pore water pressure of a partially sealed tunnel in the nearly saturated soil are derived subject to the harmonic load. On this basis, the influences of water saturation and permeability coefficient on the system responses are discussed by the numerical example. It is shown that the water saturation has a great influence on the stress and pore water pressure amplitudes. In addition, the permeability in the boundary of the tunnel is reasonably described by the permeability coefficient.

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