scholarly journals Simplified Method for Consolidation Settlement Calculation of Combined Composite Foundation

2020 ◽  
Vol 2020 ◽  
pp. 1-7
Author(s):  
Fei Liu ◽  
Kang Qin ◽  
Yongsheng Han
Keyword(s):  
Pore Water Pressure ◽  
Water Pressure ◽  
Outer Boundary ◽  
Composite Foundation ◽  
Consolidation Process ◽  
Settlement Calculation ◽  
Spacing Ratio ◽  
Consolidation Settlement ◽  
Saturated Soil Foundation ◽  
Consolidation Degree

Treating weak saturated soil foundation by drainage powder jetting pile foundation can not only increase the bearing capacity of the foundation but also accelerate the drainage and consolidation process of the foundation. Having been commonly used in engineering, the plum blossom pile layout scheme is based on the foundation axisymmetric consolidation model (the powder jetting pile is the model center and the drainage board is located at the outer boundary of the model). It adopts reasonable boundary conditions and foundation seepage conditions and the method of pile-soil composite modulus and obtains the expression of the average excess pore water pressure of the composite foundation of the instantaneous loading of the drainage powder jetting pile under the simplified model. Therefore, the average consolidation degree of the foundation is acquired. The expression of the average consolidation degree can comprehensively reflect factors such as pile-soil modulus ratio, displacement ratio, drain spacing ratio, and those which affect the consolidation process of the foundation. The obtained analytical solution is of certain practical application significance for the consolidation settlement calculation of such engineering.

scholarly journals Numerical Simulation of Consolidation Characteristics of Diluted Debris Flow

2021 ◽  
Author(s):  
Danyi Shen ◽  
Zhenming Shi ◽  
Hongchao Zheng
Keyword(s):  
Debris Flow ◽  
Pore Water Pressure ◽  
Water Pressure ◽  
Reverse Direction ◽  
High Concentration ◽  
Two Phase ◽  
Consolidation Process ◽  
Graded Materials ◽  
Consolidation Settlement ◽  
Graded Material

The consolidation settlement of diluted debris flow is a complicated process of solid-liquid two-phase flow deposition. In this paper, the consolidation and settlement characteristics of uniform-graded and wide-graded debris flow materials in clear water and slurry are simulated by using this method. The results show that in the process of consolidation, sorting occurs in the top and middle position of uniform-graded materials at low concentration, while the middle particles are separated in reverse direction at high concentration. The middle particles of wide-graded material are hardly separated in the whole consolidation process. The velocity of dissipation of excess pore water pressure in the clean water is faster than that of slurry, and the dissipation time of wide-graded materials is longer than that of uniform-graded materials. The research results are helpful to reveal the mechanism of consolidation settlement of diluted debris flow in meso-scale.

Consolidation Process and Triaxial Shear Test of Consolidation Coefficient for Saturated Soft Soil in Marsh

2011 ◽  
Vol 261-263 ◽  
pp. 1755-1759
Author(s):  
Hong Jun Liu ◽  
Ying Guo ◽  
Wei Shan ◽  
Xia Xin Tao
Keyword(s):  
Pore Water ◽  
Shear Test ◽  
Pore Water Pressure ◽  
Water Pressure ◽  
Soft Soil ◽  
Water Volume ◽  
Triaxial Shear Test ◽  
Consolidation Process ◽  
Consolidation Coefficient ◽  
Consolidation Degree

The consolidation coefficient is the important parameters for soft soil foundation to predict its consolidation settlement. At present, one-way compression test is mainly used to study consolidation process and consolidation coefficient of soft soil. For saturated soft soil in marsh, through triaxial shear test, the dissipation of pore water pressure and consolidation process can be observed during the course of soil sample drainage. This study got test result bellow through above triaxial test. Firstly, pore water pressure has hysteresis effect during the consolidation process, and the reason for this is analyzed. Secondly, consolidation degree in different consolidation time can be got according to the change of discharged water volume. Thirdly, according to Terzaghi consolidation theory, consolidation coefficients can be got under different consolidation pressures. Consolidation coefficient first increases with the increasing of consolidation degree, when consolidation degree is between 40% and 80%, saturated soft soil has larger consolidation coefficient, consolidation coefficient of saturated soft soil in marsh is between 2Ч10-4 cm2 / s and 10Ч10-4cm2 / s.

Study on Artificial Island Ground Improvement Method and Effect

2014 ◽  
Vol 1030-1032 ◽  
pp. 1037-1040
Author(s):  
Jin Fang Hou ◽  
Ju Chen ◽  
Jian Yu
Keyword(s):  
Pore Water Pressure ◽  
Water Pressure ◽  
Ground Improvement ◽  
Soft Soil ◽  
Horizontal Displacement ◽  
Treatment Method ◽  
Surcharge Preloading ◽  
Porosity Ratio ◽  
Improvement Method ◽  
Consolidation Degree

The artificial island ground on an open sea is covered by thick soft soil. It must be improved before using. In accordance with a designing scheme, the ground treatment method is inserting drain boards on land and jointed dewatering surcharge preloading, the residual settlement is not more than 30cm after improvement and the average consolidation degree is more than 85%. In order to estimate ground improvement effect and construction safety, instruments are buried to monitor the whole ground improving processes. By monitoring settlement and pore water pressure, it is shown that the total ground settlement in construction is 2234mm, its final settlement is 2464mm, and consolidation degree and residual settlement respectively satisfy requirements. In ground improvement, horizontal displacement is small and construction is safe. Meanwhile, the results of soil properties and vane shear strength detection tests show the soft soil ground is greatly reduced in water content and porosity ratio, and improved in strength. It is named that the ground improvement method is reasonable and reaches expected effect.

One-dimensional consolidation of multilayered aquifer systems with viscoelastic properties induced by time-dependent groundwater drawdown

2021 ◽  
pp. qjegh2021-073
Author(s):  
Weitao Yang ◽  
Jin Xu
Keyword(s):  
Viscoelastic Properties ◽  
Numerical Solutions ◽  
Pore Water Pressure ◽  
Water Pressure ◽  
Time Dependent ◽  
Analytical Models ◽  
Consolidation Process ◽  
One Dimensional ◽  
Groundwater Drawdown ◽  
Aquifer Systems

Most analytical and semi-analytical models for pumping-induced land subsidence invoke the simplifying assumptions regarding characteristics of geomaterials, as well as the pattern of drawdown response to pumping. This paper presents an analytical solution for one-dimensional consolidation of the multilayered soil due to groundwater drawdown, in which viscoelastic property and time-dependent drawdown are taken into account. The presented solution is developed by using the boundary transformation techniques. The validity of the proposed solution is verified by comparing with a degenerated case for a single layer, as well as with the numerical solutions and experimental results for a two-layer system. The difference between the average consolidation degree Up defined by hydraulic head and that Us defined by total settlement is discussed. The detailed parametric studies are conducted to reveal the effects of viscoelastic properties and drawdown patterns on the consolidation process. It is revealed that while the effect of different drawdown response patterns is significant during the early-intermediate stages of consolidation, the viscoelastic properties may have a more dominant influence on long-term consolidation behavior, depending on the values of the material parameters, which are reflected in both the deformation process of soil layers and the dissipation of excess pore-water pressure.

scholarly journals Experimental insights into consolidation rates during one-dimensional loading with special reference to excess pore water pressure

2020 ◽  
Vol 15 (12) ◽  
pp. 3571-3591
Author(s):  
Bartłomiej Szczepan Olek
Keyword(s):  
Pore Water ◽  
Large Scale ◽  
Pore Water Pressure ◽  
Water Pressure ◽  
Small Scale ◽  
Coefficient Of Consolidation ◽  
Consolidation Process ◽  
Factors Affecting ◽  
Fine Grained ◽  
Fine Grained Soil

AbstractConsolidation rate has significant influence on the settlement of structures founded on soft fine-grained soil. This paper presents the results of a series of small-scale and large-scale Rowe cell consolidation tests with pore water pressure measurements to investigate the factors affecting the consolidation process. Permeability and creep/resistance structure factors were considered as the governing factors. Intact and reconstituted marine clay from the Polish Carpathian Foredeep basin as well as clay–sand mixtures was examined in the present study. The fundamental relationship correlating consolidation degrees based on compression and pore water pressure was assessed to indicate the nonlinear soil behaviour. It was observed that the instantaneous consolidation parameters vary as the process progresses. The instantaneous coefficient of consolidation first drastically increases or decreases with increase in the degree of consolidation and stabilises in the middle stage of the consolidation; it then decreases significantly due to viscoplastic effects occurring in the soil structure. Based on the characteristics of the relationship between coefficient of consolidation and degree of dissipation at the base, the consolidation range that complies with theoretical assumptions was established. Furthermore, the influence of coarser fraction in clay–sand mixtures in controlling the consolidation rates is discussed.

scholarly journals Numerical Modelling of Prefabricated Vertical Drain for Soft Clay Using ABAQUS

2015 ◽  
Vol 773-774 ◽  
pp. 1502-1507
Author(s):  
Saiful Azhar Ahmad Tajudin ◽  
Mohd Fairus Yusof ◽  
I. Bakar ◽  
Aminaton Marto ◽  
Muhammad Nizam Zakaria ◽  
...  
Keyword(s):  
Pore Water Pressure ◽  
Water Pressure ◽  
Soft Soil ◽  
Soft Clay ◽  
Elastic Model ◽  
Clay Layer ◽  
Soil Consolidation ◽  
Consolidation Process ◽  
Vertical Drain ◽  
Prefabricated Vertical Drain

Construction, buildings and infrastructure founded on soft clays are often affected by settlement problem. Therefore, Prefabricated Vertical Drain (PVD) is one of the best solutions to accelerate soil consolidation by shortening the drainage path. In this study, numerical investigation was carried out to pursue a better understanding of the consolidation behavior of soft clay improved with PVD. The consolidation process accelerated by PVD with surcharge of 50 kPa was analysed using the ABAQUS software by adopting an elastic model. The aim of this study is to compare the settlement and the required time to fully consolidate the soft soil at different drain spacings (1.0 m, 1.5 m and 2.0 m) for two different thickness of the clay layer. The results shows that the time required to completely consolidate the soft soil for 12 m and 20 m thickness of clay layer with different spacings are in the range of 3 months to 66 months. The settlement rate and excess pore water pressure dissipation are increased when the spacing of the drain closer.

The Influence Factors Analysis of Initial Excess Pore Water Pressure Caused by Construction of Shield Tunnels

2011 ◽  
Vol 268-270 ◽  
pp. 1295-1300
Author(s):  
Xin Jiang Wei ◽  
Wei Jun Chen ◽  
Gang Wei ◽  
An Yuan Liu
Keyword(s):  
Pore Water ◽  
Pore Water Pressure ◽  
Water Pressure ◽  
Influence Factors ◽  
Stress Transfer ◽  
Tunnel Lining ◽  
Excess Pore Water Pressure ◽  
Factors Analysis ◽  
Consolidation Settlement ◽  
Excess Pore

Excess pore water pressure caused by construction dissipated, resulting in consolidation settlement. The formula of initial excess pore water pressure around tunnel lining was deduced by stress relief theory, and its formula within the region of its distribution at any point was subsequently deduced by stress transfer theory. By comparing the measured data, shows that the calculated closed to the measured, and with the distance increased the initial excess pore water pressure decreased in a concave curve shape. When the depth of tunnel increased or the diameter decreased, would made initial excess pore water pressure between the tunnel bottom and tunnel center horizon around tunnel lining more different. At a certain depth, the mast initial excess pore water pressure above tunnel axis, away from the axis reduced; showing a similar PECK shape.

Calculation of Consolidation Coefficient and Percent Consolidation from Measured Pore Water Pressure of Soft Clay

2011 ◽  
Vol 250-253 ◽  
pp. 1889-1892
Author(s):  
Yong Mou Zhang ◽  
Jian Chang Zhao
Keyword(s):  
Pore Water ◽  
Pore Water Pressure ◽  
Water Pressure ◽  
Soft Soil ◽  
Soft Clay ◽  
Coefficient Of Consolidation ◽  
Consolidation Process ◽  
Consolidation Coefficient

Consolidation coefficient and percent consolidation of soft clay were calculated according to the measured pore water pressure of a project in Pudong Shanghai. Calculated coefficient of consolidation was one magnitude larger than the experimental one. This was in conformity with the actual consolidation process of dynamically-consolidated soft soil.

Effect of a vacuum gradient on the consolidation of dredged slurry by vacuum preloading

2020 ◽  
Author(s):  
Jun Wang ◽  
Yuanqiang Cai ◽  
Feiyu Liu ◽  
Zhe Li ◽  
Guohui Yuan ◽  
...  
Keyword(s):  
Large Scale ◽  
Fine Particles ◽  
Pore Water Pressure ◽  
Water Pressure ◽  
Soil Surface ◽  
Particle Analysis ◽  
Soil Consolidation ◽  
Vacuum Preloading ◽  
Consolidation Rate ◽  
Consolidation Degree

In this paper, a large-scale indoor model test was carried out to reinforce the dredged slurry by vacuum preloading, and the effect of the vacuum gradient on the reinforcement effect was studied. The vacuum pressure, volume of extracted water, average ground settlement and pore water pressure were monitored during the test. After the test, the water content and vane shear strength were measured, and a particle analysis test and a scanning electron microscopy test were carried out. The results indicated that a small vacuum gradient could improve the consolidation degree and strength of the soil, and the smaller the vacuum gradient is, the better the reinforcement of the soil is. In addition, reducing the vacuum gradient could decrease the differential settlement of the soil surface and alleviate the migration of fine particles to the prefabricated drainage plates; therefore, the small vacuum gradient improved the clogging of the prefabricated drainage plates and the uniformity of soil consolidation. However, reducing the vacuum gradient also extended the test period, and a vacuum gradient of 20 kPa obtained the fastest consolidation rate of the soil.

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