/pdf/development-of-methodology-for-the-design-and-construction-12m4p60fq8.pdf

Development of methodology for the design and construction of stone columns

Seismic behavior of geosynthetic encased columns and ordinary stone columns

This paper describes a three-dimensional (3D) numerical analysis of a test embankment on geotextile-encased columns (GECs), in comparison with two-dimensional (2D) axisymmetric and plane strain analyses. The 3D numerical analysis was performed considering a rectangular strip under the embankment centerline. The 2D analysis was also carried out using axisymmetric unit cell and plane strain approaches. Numerical results indicated that the adopted 3D strip model represented well the measured deformations and pore pressure evolution during embankment construction and post-contraction periods. Unlike the unit cell model, both plane strain and 3D analyses could properly determine the settlement profile along the embankment base as well as the profile of the horizontal soil deformation beneath the embankment toes. The plane strain analysis, however, was not able to compute the geotextile ring force which might be simply calculated using the axisymmetric unit cell approach. The paper also showed that, due to horizontal boundary fixities applied to the embankment borders, the unit cell model clearly underestimated the tension developed in the basal geogrid.

A comparative study for the performance of encased granular columns

On the shear failure mode of granular column embedded unit cells subjected to static and cyclic shear loads

In order to find a more effective method in structural optimization, an improved wolf pack optimization algorithm was proposed. In the traditional wolf pack algorithm, the problem of falling into local optimum and low precision often occurs. Therefore, the adaptive step size search and Levy's flight strategy theory were employed to overcome the premature flaw of the basic wolf pack algorithm. Firstly, the reasonable change of the adaptive step size improved the fineness of the search and effectively accelerated the convergence speed. Secondly, the search strategy of Levy's flight was adopted to expand the search scope and improved the global search ability of the algorithm. At last, to verify the performance of improved wolf pack algorithm, it was tested through simulation experiments and actual cases, and compared with other algorithms. Experiments show that the improved wolf pack algorithm has better global optimization ability. This study provides a more effective solution to structural optimization problems.

/pdf/improved-wolf-pack-algorithm-for-optimum-design-of-truss-9e1r3kt54g.pdf

Improved Wolf Pack Algorithm for Optimum Design of Truss Structures

The installation of reinforced granular piles is a commonly adopted technique to improve load carrying capacity and reduce settlements in very soft clayey soils. This paper presents results of a series of laboratory model tests and numerical analysis carried on geosynthetic reinforced granular pile under short term loading. Unit cell concept has been adopted. Laboratory model tests were conducted on unreinforced, vertical encased, reinforced with horizontal strips and combined vertical-horizontal reinforced granular piles. The loading was applied either over the entire cylindrical tank area or only over the area of granular piles. The effects of various parameters such as reinforcement, encasement stiffness, shear strength of clay, length and diameter of granular piles have been studied. Experimental results in the form of vertical load intensity-settlement relationship have been compared with that obtained from PLAXIS 3D. The results of laboratory model tests indicated significant influence of reinforcement on the ultimate load intensity of granular piles and ultimate bearing capacity of treated ground. Lateral bulging in reinforced granular piles has also been controlled by incorporating geosynthetic materials.

/pdf/experimental-and-numerical-analysis-of-geosynthetic-23ruayjkwr.pdf

Experimental and Numerical Analysis of Geosynthetic-Reinforced Floating Granular Piles in Soft Clays

Performance of geosynthetic-reinforced granular piles in soft clays: Model tests and numerical analysis

The present paper investigates the effect of geogrid, as horizontal strips, on the ultimate load intensity and bulging of floating as well as end bearing granular piles. The laboratory model tests ...

Murtaza Hasan

Papers

Experimental and Numerical Analysis of Geosynthetic-Reinforced Floating Granular Piles in Soft Clays

Performance of geosynthetic-reinforced granular piles in soft clays: Model tests and numerical analysis

Soft soils improvement by granular piles reinforced with horizontal geogrid strips