Soil stabilization

About: Soil stabilization is a research topic. Over the lifetime, 3161 publications have been published within this topic receiving 48437 citations.

Fundamental Characteristics of Cement-Admixed Clay in Deep Mixing

Abstract: This paper examines the compressibility and strength characteristics of high water content cement-admixed clay in deep mixing applications. During curing time, both cement content and total clay water content of the clay–water–cement mixture significantly affect the strength and compressibility of the resulting stabilized clay. To ensure optimum improvement, the selection of an appropriate total clay water content for a mixture with a certain cement content is crucial. Furthermore, the fundamental parameters such as the ratio of after-curing void ratio ( eot ) and cement content ( Aw ) have been found sufficient to characterize the strength and compressibility of cement-admixed clay. The results of unconfined compression and consolidated–undrained tests have proven that the ratio eot ∕ Aw combines together the influences of clay water content, cement content, and curing time as well as curing pressure on the strength of cement-admixed clay. In addition, useful empirical relationships on deep mixing applic...

Geotechnical Tests of Sands Following Bioinduced Calcite Precipitation Catalyzed by Indigenous Bacteria

Abstract: Recentexperimentshaveshownthatexogenousbacteriacanbeintroducedintosoilforthepurposeofinducingcalciteprecipitation. A series of tests are documented in this paper that demonstrate that natural indigenous bacteria can also be stimulated to induce calcite precip- itation with measurable changes in geotechnical properties. Tests reported in this paper include a microcosm experiment with cone-penetration testing and cyclic triaxial shear tests. These experiments demonstrate that indigenous bacteria can induce significant quantities of calcite pre- cipitation, that calcite precipitation can result in measurable changes to geotechnical soil properties, and that the cyclic resistance ratio can be increased substantially with moderate levels of calcite precipitation. Using indigenous bacteria to modify soil properties is a significant step in making biomodification of soils economically viable. DOI: 10.1061/(ASCE)GT.1943-5606.0000781. © 2013 American Society of Civil Engineers. CE Database subject headings: Biological processes; Soil liquefaction; Cement; Bacteria; Soil stabilization; Earthquake. Author keywords: Biological processes; Liquefaction; Cementation; Bacteria; Calcite; Stabilization; Earthquake; Soil improvement.

Numerical Study of Reinforced Soil Segmental Walls Using Three Different Constitutive Soil Models

Abstract: A numerical finite-difference method (FLAC) model was used to investigate the influence of constitutive soil model on predicted response of two full-scale reinforced soil walls during construction and surcharge loading. One wall was reinforced with a relatively extensible polymeric geogrid and the other with a relatively stiff welded wire mesh. The backfill sand was modeled using three different constitutive soil models varying as follows with respect to increasing complexity: linear elastic-plastic Mohr-Coulomb, modified Duncan-Chang hyperbolic model, and Lade's single hardening model. Calculated results were compared against toe footing loads, foundation pressures, facing displacements, connection loads, and reinforcement strains. In general, predictions were within measurement accuracy for the end-of-construction and surcharge load levels corresponding to working stress conditions. However, the modified Duncan-Chang model which explicitly considers plane strain boundary conditions is a good compromise between prediction accuracy and availability of parameters from conventional triaxial compression testing. The results of this investigation give confidence that numerical FLAC models using this simple soil constitutive model are adequate to predict the performance of reinforced soil walls under typical operational conditions provided that the soil reinforcement, interfaces, boundaries, construction sequence, and soil compaction are modeled correctly. Further improvement of predictions using more sophisticated soil models is not guaranteed.

Parameters Controlling Tensile and Compressive Strength of Artificially Cemented Sand

Abstract: The enhancement of local soils with cement for the construction of stabilized pavement bases, canal lining, and support layer for shallow foundations shows great economical and environmental advantages, avoiding the use of borrow materials from elsewhere, as well as the need of a spoil area. The present research aims to quantify the influence of the amount of cement, the porosity, and the voids/cement ratio in the assessment of unconfined compressive strength qu and splitting tensile strength qt of an artificially cemented sand, as well as in the evaluation of qt /qu relationship. A program of splitting tensile tests and unconfined compression tests considering three distinct voids ratio and seven cement contents, varying from 1 to 12%, was carried out in the present study. The results show that a power function adapts well qt and qu values with increasing cement content and with reducing porosity of the compacted mixture. The voids/cement ratio is demonstrated to be an appropriate parameter to assess both qt and qu of the sand-cement mixture studied. Finally, the qt /qu relationship is unique for the sand-cement studied, being independent of the voids/cement ratio. DOI: 10.1061/ASCEGT.1943-5606.0000278 CE Database subject headings: Tensile strength; Compressive strength; Soil cement; Compacted soils. Author keywords: Tensile strength; Compressive strength; Soil cement; Compacted soils.