Keywords: Fondation ; Mur de soutenement ; Pieux ; Capacite portante ; Ancrage ; Dimensionnement Reference Record created on 2004-09-07, modified on 2016-08-08

Foundation analysis and design

Wzmocnienie posadowienia obiektów energetycznych za pomocą mikropali iniekcyjnych wciskanych

Some road systems are unpaved due to limited governmental finance and fewer maintenance techniques. Such unpaved roads become vulnerable during heavy rainy seasons following restrained accessibility among cities and traffic accidents. Considering the circumstances, innovative and cost–effective approaches are required for unpaved roads. Microbially induced carbonate precipitation (MICP) is an emerging soil improvement technology using microbes to hydrolyze urea generating carbonate ions, and precipitates calcium carbonate in the presence of calcium ion. Induced calcium carbonate bonds soil particles enhancing stiffness and strength when the MICP reaction takes place within the soil system. This study introduces the use of microbes on unpaved road systems consisting of in situ lateritic soils. The MICP technology was implemented to improve soil strength through two approaches: surface spraying and mixing methods. A series of soil testing was performed with varying chemical concentrations to measure precipitation efficiency, strength, and quality for construction material and see the feasibility of the proposed methods. The laboratory test results indicated that the surface spraying method provided improved; however, it was highly affected by the infiltration characteristics of used soils. The mixing method showed promising results even under submerged conditions, but still required improvement. Overall, the proposed idea seems possible to apply to improving unpaved road systems in the lateritic region but requires further research and optimization.

/pdf/preliminary-study-on-application-and-limitation-of-2motox2q.pdf

Preliminary Study on Application and Limitation of Microbially Induced Carbonate Precipitation to Improve Unpaved Road in Lateritic Region

- Due to the proximity of the bedrock , rock socketed bored and cast in-situ piles are used to support the heavy super structure loads from the high-rise structures transferring to bedrock. In order to design single piles or group of piles, it is very important to know the carrying capacity of the bedrock in terms of skin friction distribution along the pile shaft and the load carried by the pile toe. Such information can be obtained by using the instrumented pile load tests but the instrumented pile load tests are expensive and not always carried out in most of the piling sites in Sri Lanka. In this study, it was aimed to find out the carrying capacity of cast in-situ bored single piles using commonly used finite element software PLAXIS 2D and compare the results with the instrumented pile load test results obtained in the field. Prior to the use of software package based on finite element analysis to find out the carrying capacity of the pile, the accuracy of the model used was verified by the results instrumented pile load test and the nearby borehole test results. Further, the differences and the difficulties of the interpretation of results with their potential reasons were discussed within the study. In the current study, the soil and rock properties were used from the nearby borehole results. It was shown that the best match results with the field instrumented pile load tests for weathered rocks were obtained when the elastic modulus for rock layers were twice the value suggested by Hong Kong geo guidelines (Geo,2006) whereas the best match results with instrumented pile load test results were given when half the value of the Young’s modulus of rock suggested by the Hong Kong geo guidelines (Geo,2006). finite element study was conducted using PAXIS 2D computer package to predict the settlement behaviour and to predict the bearing capacity of bored and cast in-situ piles of Sri Lanka. Analyses were conducted changing the compressibility and shear strength properties of since, settlement and bearing capacity of the piles were directly with the compressibility and shear strength properties of rock. The conclusions obtained from this study can be summarized as the modulus of rock mass is under predicted by the Hong Kong geo guide for weathered rocks, by increasing the modulus of rock mass twice as the original value obtained from Hong Kong geo guide for weathered rocks gives a reasonable result for settlement, skin friction and end bearing of the pile, whereas the modulus of rock mass is over predicted by the Hong Kong geo guide for fresh rock, by taking the half of the modulus from the original obtained from Hong Kong geo guide gives reasonable for pile capacity and settlement of the pile. The selection of the and undisturbed parameters

/pdf/comparison-of-instrumented-pile-load-test-results-with-1yvsp543.pdf

Comparison of Instrumented Pile Load Test Results with Finite Element Simulation

In this study a numerical examples and solutions has been obtained by using three system of beam resting on elastic foundation (BOEF) which was adopted previously by three different engineering software. The first part of this paper was related to verify the model of (BOEF) by using ETABS2015 by make a comparison with previous results by determination the maximum settlements at the mid of span which show a good agreement between ETABS2015 and other results, where the total differences was vary from 2.13 % to 3.27%. . The second part of this study was highlighted on the settlement of BOEF with different parametric study (beam thickness, soil subgrade reaction(KS) and the load location), case (1) was selected for this goal. In this paper it is found that the differential settlement along the beam are decrease as increasing in the beam stiffness in addition to possibility to obtain uplift (positive settlement ) for some type of changing in the load location specially for higher thick beam . It was noticed that the settlement are increased significantly as reducing in the (KS). Finally this study show a different form of deflection by combination two of parametric study.

/pdf/determination-of-settlement-for-beam-on-elastic-foundation-39a5vgp8c3.pdf

Foundation analysis and design

Citations

Wzmocnienie posadowienia obiektów energetycznych za pomocą mikropali iniekcyjnych wciskanych

Preliminary Study on Application and Limitation of Microbially Induced Carbonate Precipitation to Improve Unpaved Road in Lateritic Region

Comparison of Instrumented Pile Load Test Results with Finite Element Simulation

Determination of Settlement for Beam on Elastic Foundation by ETABS Software

Experimental Testing and Analytical Modeling of Driven Steel Pile Bridge Bents

Related Papers (5)

Soil mechanics in engineering practice

Theoretical Soil Mechanics

Pile Foundation Analysis and Design

Principles of Foundation Engineering

Analysis of Ultimate Loads of Shallow Foundations