Undrained Uniaxial Capacities of Suction Bucket Foundations in Rows

2018 ◽  
Author(s):  
Zhong Xiao ◽  
Yumin Lu ◽  
Ying Liu
Keyword(s):  
Finite Element ◽  
Shear Strength ◽  
Soft Soil ◽  
Failure Mechanisms ◽  
Soft Clay ◽  
Finite Element Models ◽  
Simple Construction ◽  
Bucket Foundation ◽  
Spacing Ratio ◽  
Soil Shear Strength

Suction bucket foundations in rows, sunk by self-weight and passive suction, can be used as footings of breakwater, trestle bridge, offshore cofferdam and other structures, and they have a fine application prospect on soft soil for their advantages of good bearing capacities, simple construction, low investment, being reusable and so forth. A large number of finite-element models for suction bucket foundations in undrained soft clay were established to investigate uniaxial capacities of suction bucket foundations, and the effects of foundations spacing ratio, embedment ratio and soil shear strength were studied. The results show that foundations spacing ratio has certain effect on the uniaxial capacities of a suction bucket foundation but is less influential than other factors; embedment ratio and soil shear strengths have more influence on the uniaxial bearing capacities and failure mechanisms of bucket foundation. Based on these results, simplified formulae are proposed to predict uniaxial capacities of suction bucket foundations in rows for designers to use directly.

UTILISATION OF PLASTIC SACKS FIBRE AND BRAN ASH FOR SOFT CLAY SHEAR STRENGTH

2016 ◽  
Vol 78 (8-5) ◽  
Author(s):  
Nyimas Septi Rika Putri ◽  
Ratna Dewi ◽  
Muhammad Ilham
Keyword(s):  
Shear Strength ◽  
Soft Soil ◽  
Soft Clay ◽  
Dry Weight ◽  
Strength Properties ◽  
Optimum Level ◽  
Soil Stabilisation ◽  
Strength Tests ◽  
Bearing Load ◽  
Soil Shear Strength

Soft soil possess poor mechanical properties, thus produce problems when bearing load. To overcome the problems, soft soil has to be stabilised. To do soil stabilisation, it Is imperative to add some mixture as additional substance in order to improve the characteristic of the soft soil. Plastic sacks fibre is one of the easily obtainable material which consists of high density profile, while bran ash contains good carbon and silica. This research aimed to determine the optimum level of plastic sacks waste fibre and bran ash to obtain the maximum soil shear strength and to compare the original soil shear strength with the modified mixture soil shear strength. The strength tests were conducted on the laboratory scale using the triaxial test device for the Unconsolidated Undrained (UU) test. Soft clay sample was mixed with the chop of plastic sacks fibre with the following level of composition : 0.4 % , 0.6 %, 0.8 %, 1 %, and also the bran ash composition content of  0 %, 2 % and 4 % to the dry weight of soil with the test unit of 36 pieces. Based on laboratory testing, the maximum cohesion value reside on variation of 0.8 % plastic sacks fibre and 2 % bran ash with the value of 0.65 kg/cm2, and the maximum shear angle lays on variation of 1 % of plastic sacks fibre and 0 % of bran ash with the value of 9.95 degree. For the mixture variation of 0.8 % plastic sacks fibre and 2 % of bran ash, it produced a shear strength of 0.67 kg/cm2 and abled to increase the soil shear strength by 87.08 %. As a conclusion, the use of plastic sacks fibre and bran ash was found to be able to improve the soft clay shear strength properties.

Finite Element Modeling of a Mechanically Stabilized Earth Trial Wall

2021 ◽  
pp. 036119812110164
Author(s):  
Andrew Lees ◽  
Michael Dobie
Keyword(s):  
Finite Element ◽  
Shear Strength ◽  
Retaining Wall ◽  
Back Analysis ◽  
Soil Parameters ◽  
Failure Behavior ◽  
Valuable Insight ◽  
Deformation And Failure ◽  
First Case ◽  
Soil Shear Strength

Polymer geogrid reinforced soil retaining walls have become commonplace, with routine design generally carried out by limiting equilibrium methods. Finite element analysis (FEA) is becoming more widely used to assess the likely deformation behavior of these structures, although in many cases such analyses over-predict deformation compared with monitored structures. Back-analysis of unit tests and instrumented walls improves the techniques and models used in FEA to represent the soil fill, reinforcement and composite behavior caused by the stabilization effect of the geogrid apertures on the soil particles. This composite behavior is most representatively modeled as enhanced soil shear strength. The back-analysis of two test cases provides valuable insight into the benefits of this approach. In the first case, a unit cell was set up such that one side could yield thereby reaching the active earth pressure state. Using FEA a test without geogrid was modeled to help establish appropriate soil parameters. These parameters were then used to back-analyze a test with geogrid present. Simply using the tensile properties of the geogrid over-predicted the yield pressure but using an enhanced soil shear strength gave a satisfactory comparison with the measured result. In the second case a trial retaining wall was back-analyzed to investigate both deformation and failure, the failure induced by cutting the geogrid after construction using heated wires. The closest fit to the actual deformation and failure behavior was provided by using enhanced fill shear strength.

The Effect of Heat Induction on Shear Strength of Soft Soil in Radial Zone

2020 ◽  
Vol 998 ◽  
pp. 329-334
Author(s):  
Maraden Panjaitan ◽  
Lawalenna Samang ◽  
Achmad Bakri Muhiddin ◽  
Tri Harianto
Keyword(s):  
Compressive Strength ◽  
Shear Strength ◽  
Soft Soil ◽  
Soft Clay ◽  
Experimental Result ◽  
Small Scale ◽  
Infrastructure Development ◽  
Heat Induction ◽  
Vane Shear Test ◽  
Radial Zone

The main problem in infrastructure development at the soft clay was its bearing capacity therefore it needs to be improved. In this research, the improvement method was carried out by modeling in small scale of preloading and heat induction combination. Location of soft clay sampling was in Takalar, Indonesia. The purpose of this study was to investigate the change of the shear strength of soft soil corresponding with heat induction at the radial zone. The shear strength was obtained by vane shear test and compressive strength from unconfined compressive test (UCT). The heat applied ranging from 100o C, 200o C, 300o C, and 400o C with static preloading load 0.20 kg/cm2. The strengths of the soil in radial zones have been tested at R0, R1, and R2. At lowest temperature 100° at R0 the compressive strength was 0.203 kg/cm2, at highest temperature 400° at R0 the compressive strength 0.467 kg/cm2, there was a significant increasing of compressive strength value with the change of temperature. At the highest temperature 4000 the shear strength from vane shear tests resulting at R0 0.240 kg/cm2, R1 of 0.128 kg/cm2, R2 of 0.077 kg/cm2. At the lowest temperature of 100o C shows R0 at 0.116 kg/cm2, R1 at 0.070 kg/cm2, R3 of 0.046 kg/cm2. The results show a tendency of declining strength value as the soil farther away from center of heat induction. The experimental result from this model produces strength that can be used as a parameter of the foundation model on soft soil.

scholarly journals STUDI SIFAT MEKANIS TANAH MERAH DENGAN PENGUJIAN TRIAKSIAL

2018 ◽  
Vol 7 (1) ◽  
pp. 29-34
Author(s):  
Redaksi Tim Jurnal
Keyword(s):  
Shear Strength ◽  
Soil Type ◽  
Clay Soil ◽  
Soft Soil ◽  
Soft Clay ◽  
Liquid Limit ◽  
Red Soil ◽  
Triaxial Tests ◽  
Limit Value ◽  
Triaxial Apparatus

Characteristics soft soil can cause instability and long-term degradation problems. This is because the soil has a low shear strength value and high compressibility. One type of soil belonging to the soft soil type is soft clay soil. Red soil belongs to the soft clay soil type. Therefore, the purpose of this research to determines the parameters of the shear strength of red soil in the area of Pakjo City Palembang, South Sumatra Province. The equipment had been used to obtain parameters of mechanical properties of red soil was using Triaxial apparatus. The results of the red soil properties index include: water content value (□ 27.70%, specific gravity value (Gs) 2.67, liquid limit value (LL) 66.00%, value of plastic limit of 25.13% and index value (IP) of 40.87% Classification of soil CH (USCS) and A-7-6 (AASHTO). The result of the Triaxial tests was the value of cohesion (c): 16.25-18, 15 kPa, and internal friction (□): 13.50-14.75⁰. The result of shear strength (□) : 17.68-24.02 kPa. The shear strength value of red soil indicates soil which includes soft soil (12.5-25 kPa).

Quasi-Dynamic Implicit Finite Element Analysis of Steel-Clad, Wood-Framed Shear Walls

2020 ◽  
Vol 63 (6) ◽  
pp. 1619-1628
Author(s):  
Khoi D. Mai ◽  
William F. Cofer ◽  
Donald A. Bender
Keyword(s):  
Finite Element Analysis ◽  
Finite Element ◽  
Shear Strength ◽  
Shear Walls ◽  
Monotonic Loading ◽  
Solution Technique ◽  
Finite Element Models ◽  
Ultimate Shear Strength ◽  
Element Analysis ◽  
Wood Frame

HighlightsA new finite element modeling method was developed to predict performance of steel-clad, wood-framed diaphragms.The new method overcomes limitations of previous models and accurately predicts yielding and buckling behaviors.The new method will save time and money in developing design values for steel-clad, wood-frame diaphragms.Abstract. Various finite element codes and solution techniques have been developed for steel-clad, wood-framed (SCWF) shear walls over the past few decades. Most previous finite element models for SCWF shear walls under monotonic loading were based on a static implicit solution technique. Previous researchers stated that the static implicit technique showed promise for modeling SCWF diaphragms; however, the solution technique failed to converge to equilibrium as local instabilities in the form of snap-through buckling of steel cladding occurred or geometric nonlinearities were included in the model. In this study, a nonlinear quasi-dynamic implicit finite element analysis (FEA) of SCWF shear walls subjected to monotonic loading was developed to overcome the deficiencies of the static implicit approach. Three types of elements were used, including beam elements to model wood framing, shell elements to model steel cladding, and nonlinear spring elements to model connectors. Screw connector tests were conducted to obtain the load-displacement constitutive relationships needed for finite element models. Nine types of SCWF shear walls with and without lap seam stitching were tested to validate the finite element model. The ratios of predicted to test values for ultimate shear strength averaged 0.97 with a coefficient of variation (COV) of 8.1%, and the ratios for effective shear modulus averaged 1.13 with a COV of 30%. The quasi-dynamic implicit FEA is a significant improvement over previous static implicit techniques and should be a useful tool to predict the ultimate shear strength and effective shear modulus of SCWF shear walls under monotonic loading. Keywords: Diaphragm design, Post-frame building, Steel-clad wood-frame diaphragm.

An approximate method for estimating the stability of geotextile-reinforced embankments

1985 ◽  
Vol 22 (3) ◽  
pp. 392-398 ◽  
Author(s):  
R. K. Rowe ◽  
K. L. Soderman
Keyword(s):  
Finite Element ◽  
Shear Strength ◽  
Limit Equilibrium ◽  
Soft Clay ◽  
Soil Reinforcement ◽  
Short Term ◽  
Critical Height ◽  
Reinforced Embankments ◽  
The Stability ◽  
Conventional Limit

A method of estimating the short-term stability of reinforced embankments constructed on a deposit that can be idealized as being uniform and purely cohesive is described. This approach maintains the simplicity of conventional limit equilibrium techniques while incorporating the effect of soil–geotextile interaction in terms of an allowable compatible strain for the geotextile. This allowable compatible strain may be deduced from a design chart and depends on the foundation stiffness, the embankment geometry, the depth of the deposit, and the critical height of an unreinforced embankment. The procedure is checked against finite element results and against one published case history. Key words: embankment, geotextile, analysis, limit equilibrium, finite element, soft clay, shear strength, soil reinforcement.

Limit analysis and finite element evaluation of lateral pipe–soil interaction resistance

2016 ◽  
Vol 53 (1) ◽  
pp. 14-21 ◽  
Author(s):  
W.O. McCarron
Keyword(s):  
Finite Element ◽  
Monte Carlo ◽  
Shear Strength ◽  
Monte Carlo Simulations ◽  
Limit Analysis ◽  
Soil Conditions ◽  
Cohesive Soils ◽  
Perfectly Plastic ◽  
Soil Shear Strength ◽  
Upper Bound Technique

The lateral breakout soil resistance of pipelines supported on undrained cohesive soils determined from limit analysis and finite element methods are compared for a linearly increasing soil strength profile. The limit analysis solution is based on an upper-bound technique. The finite element solutions are developed from coupled Eulerian–Lagrangian simulations. The capacities determined by the two methodologies are in close agreement for the perfectly plastic soil conditions. The relative ease with which the limit analysis solutions are obtained allows rapid investigation of the implications of uncertainty of the soil shear strength profile and pipe embedment via Monte Carlo simulations. Monte Carlo simulations illustrate the implications of correlated random variables describing the shear strength profile and pipe embedment.

scholarly journals Bearing Capacity of the Working Platform with Kinematic Method

2015 ◽  
Vol 37 (1) ◽  
pp. 3-8
Author(s):  
Katarzyna Białek ◽  
Lech Bałachowski
Keyword(s):  
Shear Strength ◽  
Bearing Capacity ◽  
Soft Soil ◽  
Failure Mechanisms ◽  
Cohesionless Soils ◽  
Angle Of Internal Friction ◽  
Kinematic Method ◽  
Margin Of Safety ◽  
Effective Angle ◽  
Different Thickness

Abstract Bearing capacity of the working platform for heavy tracks was analysed using Distinct Layout Optimization (DLO) method. The platform layer constructed from cohesionless soils is resting on weak cohesive subgrade. Different thickness of the platform, its effective angle of internal friction and undrained shear strength of the soft soil were taken into consideration. Kinematic method permits different failure mechanisms to be analyzed. Margin of safety for a given load and subsoil conditions was determined using two approaches: increasing the load or decreasing the shear strength up to failure. The results were compared with solution proposed in BRE recommendations.

Penetration and uplift resistances of two interfering pipelines buried in clays

2021 ◽  
pp. 2150020
Author(s):  
Sorawit Seehavong ◽  
Suraparb Keawsawasvong
Keyword(s):  
Finite Element ◽  
Shear Strength ◽  
Limit Analysis ◽  
Failure Mechanisms ◽  
Ground Surface ◽  
Linear Increase ◽  
Unit Weight ◽  
Cohesive Soils ◽  
Input Parameters ◽  
Bearing Loads

The primary aim of this paper is to determine penetration and uplift resistances of two interfering pipelines buried in clay with a linear increase in strength. The advanced finite element limit analysis of upper and lower bound theorems is used to perform new limit analysis solutions for both penetration and uplift resistances of two interfering pipelines. The strength profiles of cohesive soils are the cases of normally consolidated clays in deep water by setting the shear strength at the ground surface to be zero and linearly increased with the depth. The twin pipelines have the same geometries and are simultaneously failed at the same magnitude of the failure uplift or bearing loads. There are three considered input parameters including the spacing between the pipes, the embedded depth of the pipes, and the unit weight of soils. All input parameters have significant influences on the penetration and uplift resistances of two interfering pipelines. Failure mechanisms of the problems are also investigated, and stability charts of the penetration and uplift resistances of two interfering pipelines are produced for practical uses in offshore geotechnical engineering.

Sign in / Sign up

Export Citation Format

Share Document