Investigation of Engineering Properties of Cement-Stabilized Calcareous Sand Foundation

Yuan Chai,Hai-Bo Lyu,Fu-Jiang Wang,Dai-Ping Jiang,Ivan Giorgio

doi:10.1155/2021/9188560

Abstract

Calcareous sand is widespread around Nansha Islands, South China Sea. In oceanic and coastal engineering, calcareous sand is usually used as a building foundation and backfill material for airport runway embankments. The engineering characteristics of calcareous sand is different from terrigenous sand because of its irregular grain shape, lower particle strength, and internal voids, which have caused many engineering problems in the last decades. Cement-stabilized soil, as a common foundation reinforcement method, can solve these engineering problems and improve the foundation strength effectively. Therefore, it is very important to estimate the engineering characteristics of cement-stabilized calcareous sand foundations. In this paper, the basic engineering characteristics, bearing capacity, and deformational behavior of calcareous sand were studied by carrying out a series of tests on cement-stabilized calcareous sand. It is found that: (1) the uniaxial compression strength of calcareous sand is higher than that of Guangzhou soft soil but lower than that of filter medium quartz sand; (2) the deformation of the calcareous sand under compression is mainly plastic, and the elastic deformation gradually increases with increasing cement content; (3) the apparent cohesion of calcareous sand increases, while internal friction angle decreases with increasing cement content; (4) cement-stabilized method can significantly improve the bearing capacity of calcareous sand foundation, especially for the saturated state. A cement content equal to or more than 15% and a thickness of 1/8 of the foundation can effectively improve the bearing capacity of the foundation; and (5) the ultimate bearing capacity of the foundation by numerical calculation is higher than that by experiments, while the settlement by calculating is lower.

Highlights

Calcareous sand, which consists of skeletal remains of marine organisms, is mainly distributed on the surroundings of islands and seashores throughout the world, such as the South China Sea, Red Sea, and waters of Western Australia [1]
E special properties of calcareous sands have caused many engineering problems in the last decades. e first engineering problem occurred in the 1960s when the ESSO Australia designed the pile system of the construction of a project in calcareous sands near the Bass Strait that pile driving was easier than expected during production platform installation [5]
A series of laboratory experiments were conducted on calcareous sand from the South China Sea to investigate the engineering characteristics of cement stabilized calcareous sand. e main conclusions are as follows: (1) e UCS of calcareous sand with cement contents of 5%, 10%, and 15% at different curing times was obtained. e UCS of the cemented calcareous sand is higher than that of cemented Guangzhou soft soil but lower than that of quartz sand

Summary

Introduction

Calcareous sand, which consists of skeletal remains of marine organisms, is mainly distributed on the surroundings of islands and seashores throughout the world, such as the South China Sea, Red Sea, and waters of Western Australia [1]. Because the calcareous sands consist of shells fragments and corals debris, the shape of calcareous sand particles are quite irregular, and the particles could be crushed [2]. As a result, their geotechnical properties are quite different from those of quartz sand and other terrigenous soils. E special properties of calcareous sands have caused many engineering problems in the last decades. E first engineering problem occurred in the 1960s when the ESSO Australia designed the pile system of the construction of a project in calcareous sands near the Bass Strait that pile driving was easier than expected during production platform installation [5]. In the tropical and subtropical regions around the Pacific Ocean, calcareous sand is distributed in shallow water and near the coast, such

Methods

Results

Conclusion