The Analysis of Vacuum-Surcharge Preloading Method with FLAC3D

2013 ◽  
Vol 405-408 ◽  
pp. 151-154
Author(s):  
Chun Yuan Liu ◽  
Song Shen ◽  
Jie Li ◽  
Peng Chao Zhang
Keyword(s):  
Soft Soil ◽  
Water Discharge ◽  
Soil Layer ◽  
Real Situation ◽  
Actual Measurement ◽  
A Value ◽  
Multi Stage ◽  
Surcharge Preloading ◽  
Foundation Deformation ◽  
Preloading Method

Based on the test section on the expressway in Jiangsu, the thesis makes a model and then conducts numerical simulation on the settlement of soft soil subgrade by using FLAC3D. The author set the filling layer null, and assigns a value to the loaded soil layer according to the construction sequence to realize multi-stage loading. The thesis also analyzes the pore water discharge and foundation deformation when the soil is consolidated. It shows that the simulation result is very close to actual measurement result, and can clearly demonstrate the real situation of settlement.

scholarly journals Reliability Design of Soft Soil Foundation Preloading Method for Airport Runway

2019 ◽  
Vol 2019 ◽  
pp. 1-8 ◽  
Author(s):  
Qingkun Yu ◽  
Liangcai Cai ◽  
Xiang Shi
Keyword(s):  
Treatment Plan ◽  
Soft Soil ◽  
Soil Layer ◽  
Probability Of Failure ◽  
Soil Parameters ◽  
Reliability Calculation ◽  
Soil Foundation ◽  
Soft Soil Foundation ◽  
Airport Runway ◽  
Preloading Method

Focusing on the rapid assessment of the reliability of airport runway soft soil foundation, taking the soft soil foundation preloading method as the research object, we established the corresponding settlement calculation model and studied the soil parameters and how they affect the settlement values, and the reliability of the soft soil foundation preloading method was obtained by the checking point method (JC). In order to realize the fast calculation of reliability, Visual Studio 2010 is used to design the visual reliability calculation program of the airport runway soft soil foundation preloading method. The analysis results showed that the soil index with the greatest influence on the final consolidation settlement was the compression coefficient, followed by the soil layer thickness, the compression modulus, the void ratio, and the consolidation coefficient. On the basis of the limit state equation, we got the final failure probability formula. Combined with an airport project example, the reliability calculation results showed that the longer the preloading time was, the more reliable the treatment plan was, and the less the probability of failure was; the larger the preloading pressure was, the more reliable the treatment plan was, and the less the probability of failure was. In the engineering example, it can be found that the treatment plan with the preloading of 100 kPa and the stacking time of 150 days is the best solution.

Case Study on Soft Foundation of Coastal Saline Soil

2014 ◽  
Vol 1065-1069 ◽  
pp. 469-474
Author(s):  
Jun Sun ◽  
Hai Jun Chen ◽  
Si Hai Wang ◽  
Hong Mei Li
Keyword(s):  
Membrane Separation ◽  
Saline Soil ◽  
Soil Layer ◽  
Coastal Saline Soil ◽  
Surcharge Preloading ◽  
Layer Composite ◽  
Vane Shear Test ◽  
Embankment Height ◽  
Soil Foundation ◽  
Preloading Method

Coastal saline soil foundation was consolidated by surcharge preloading method based on the improving constructio technol-ogy. For instance,setting sand gravels separation layer,composite geo-membrane separation layer,improve embankment height, etc. The monitoring results are analyzed including the ground with every soil layer settlement. Combining with the test result of the shear strength of vane shear test and various ion content of soil samples,it is concluded that reinforcement effect of seashore saline soil consolidated by surcharge preloading method,at the same time, exclusion salt and reduce damage of the foundation.

scholarly journals CONCERNING THE EXTRACTION OF A SLACK SOIL LAYER FROM COMPRESSIBLE THICKNESS OF FOUNDATION STRATUM OF FINITE WIDTH FOUNDATIONS

2019 ◽  
Vol 7 (4) ◽  
pp. 49-56
Author(s):  
Zaven Ter-Martirosyan ◽  
Armen Ter-martirosyan ◽  
Valery DEMYANENKO
Keyword(s):  
Analytical Solutions ◽  
Soft Soil ◽  
Soil Layer ◽  
Horizontal Displacement ◽  
Creep Model ◽  
Shear Stresses ◽  
Finite Width ◽  
Relative Depth ◽  
Weak Layer ◽  
Horizontal Displacements

The paper provides a quantitative assessment of the deflected mode of foundation stratum of finite width foundation, in the compressible thickness of which there is a slack clay soil layer. A number of criteria for assessing the possibility or impossibility of extruding a slack layer depending on its strength and rheological properties, as well as the relative thickness of the layer to its length (h/l) and the relative depth of the layer (h/d) have been given. Closed analytical solutions are given to determine the rate of Foundation precipitation depending on the rate of extrusion of the weak layer, including taking into account the damped and undamped creep. The analytical solutions in the article are supported by the graphical part made with the help of the Mathcad program. Plots of changes in shear stresses in the layer along the x axis at different distances from the axis and at different values 0, contours of horizontal displacement velocities in the weak layer at different distances from the x axis, plots of horizontal displacement velocities in the middle of the weak layer and plots of horizontal displacement velocities in the weak layer at different distances from the x axis are given. As a calculation model for describing the creep of a slack layer, rheological ones of the soil using power and hyperbolic functions and their modifications have been considered. In addition, most modern rheological models that take into account soil hardening during creep have been considered. Based on these models, the problem is solved by means analytical and numerical methods using the Mathcad PC and the PLAXIS PC according to the Soft Soil Creep model. The graphical part shows the isofields of horizontal displacements for 300 days and 600 days and the corresponding contours of horizontal displacements.

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.

Model Test of Bearing Capacity of WasteTire Assembly Foundation on Soft Soil Layer

2021 ◽  
Vol 69 (7) ◽  
pp. 263-269
Author(s):  
Me ti ◽  
Tri Harianto ◽  
Abdul Rachman Djamaluddin ◽  
Achmad Bakri Muhiddin
Keyword(s):  
Bearing Capacity ◽  
Model Test ◽  
Soft Soil ◽  
Soil Layer

Soft soil layer-tunnel interaction under seismic loading

2020 ◽  
Vol 98 ◽  
pp. 103329 ◽  
Author(s):  
Qiangqiang Sun ◽  
Daniel Dias ◽  
Luis Ribeiro e Sousa
Keyword(s):  
Soft Soil ◽  
Soil Layer ◽  
Seismic Loading

Stability Analysis of Narrow and Long Excavation in Soft Soil Area

2015 ◽  
Vol 723 ◽  
pp. 372-376
Author(s):  
Shi Chong Zhou ◽  
Li Li Gao ◽  
Dong Hui Wu ◽  
Yang Liu ◽  
Dong Yue Wang ◽  
...  
Keyword(s):  
Reduction Method ◽  
Soft Soil ◽  
Soil Layer ◽  
Spatial Effect ◽  
Strength Reduction ◽  
Strength Reduction Method ◽  
Present Stage ◽  
Support Structure ◽  
Finite Element Software ◽  
Sliding Stability

At the present stage of excavation design,the embedded depth of braced structure should meet the requirement of circular sliding stability when the bottom is soft soil. By increasing the embedded depth of support structure, the requirements of stability could be meet. In the normal design, the support structure must penetrate the soft soil layer when the bottom exist soft soil. While when the excavation is narrow and long, because of the obviously spatial effect, there is no need to determine the embedded depth based on the general circular sliding stability. In this paper, based on one the project example, calculate and analyze the similar stability using strength reduction method through the finite element software Plaxis and Midas.

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