Research on the Densification of Vibroflotation against Liquefaction for Filling Coral Sand

The stress wave attenuation and energy absorption in the coral sand were respectively investigated. A series of experiments were carried out by using a new methodology with an improved split Hopkinson pressure bar (SHPB). Four types of coral sand, i.e., particle sizes of 1.18–0.60 mm, 0.60–0.30 mm, 0.30–0.15 mm, and 0.15–0.075 mm, were carefully sieved and tested. Significant effects of coral sand on stress wave attenuation and energy absorption were observed. Correlation between stress wave attenuation and energy absorption of coral sand was validated. Conclusions on particle size effect of stress wave attenuation and energy absorption, which support each other, were drawn. There existed a common critical stress zone for coral sand with different particle sizes. When the stress below this zone, sand with small particle sizes attenuates stress wave better and absorb energy more; when the stress beyond this zone, sand with larger particle sizes behave better on stress wave attenuation and energy absorption.

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Research on Integrated Liquefaction Assessment for Stone Column Applied in Coral Sand Area within High Earthquake Magnitude Zone

IOP Conference Series Earth and Environmental Science ◽

10.1088/1755-1315/638/1/012077 ◽

2021 ◽

Vol 638 (1) ◽

pp. 012077

Author(s):

Xiaocong Liang ◽

Pingshan Chen ◽

Qingchang Qiu ◽

Jing Wang ◽

Mingxing Zhu

Keyword(s):

Earthquake Magnitude ◽

Stone Column ◽

Coral Sand ◽

Liquefaction Assessment

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Coral sand solidification test using ureolytic bacteria

Geomechanics from Micro to Macro ◽

10.1201/b17395-276 ◽

2014 ◽

pp. 1521-1526 ◽

Cited By ~ 3

Author(s):

T Danjo ◽

S Kawasaki ◽

S Shimazaki ◽

K Koizuka

Keyword(s):

Coral Sand ◽

Ureolytic Bacteria

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PLANNING OF SOFT SOIL IMPROVEMENT WITH PRELOADING AND PREFABRICATED VERTICAL DRAIN METHOD

Jurnal Rekayasa Sipil dan Lingkungan ◽

10.19184/jrsl.v2i01.7543 ◽

2018 ◽

Vol 2 (01) ◽

pp. 19

Author(s):

Ana Crosita Ningsih ◽

Luthfi Amri Wicaksono ◽

Mokhamad Farid Ma'ruf

Keyword(s):

Urban Areas ◽

Soil Structure ◽

Soft Soil ◽

Soil Improvement ◽

Building Site ◽

Planning Time ◽

Coral Sand ◽

Rapid Construction ◽

Prefabricated Vertical Drain ◽

Surrounding Areas

The northern coastal areas of Java such as Gresik and surrounding areas have a soil structure of alluvium consisting of gravel / coral, sand, clay soil and shells. Soil basic conditions are soft enough to cause land subsidence (settlement). The need for rapid construction causes the urban areas to become less and more for development land. This requires the improvement of soft soil to be used as a building site. As for the method to be done in this planning using a combination of preloading and PVD methods to accelerate the process of land degradation. Based on the planning result, the total height of embankment (preloading) is 3.5 m and the planning time lasted 4 months. Soft soil improvement is done up to 25 m depth with PVD design using triangle pattern and space 1.3 m. The 95% consolidation decrease due to the load of embankment caused the soil to fall as deep as 1,928 m. In this planning use modeling Plaxis 8.6 2D and the resulting yield of soil is 1,990 m. Wilayah pesisir pantai utara Jawa seperti daerah Gresik dan sekitarnya mempunyai struktur tanah berupa alluvium yang terdiri dari batu kerikil/koral, pasir, tanah lempung dan pecahan kulit kerang. Kondisi tanah dasar yang cukup lunak menyebabkan terjadinya penurunan tanah (settlement). Adanya kebutuhan konstruksi yang semakin pesat menyebabkan wilayah perkotaan menjadi semakin sedikit untuk dijadikan lahan pembangunan. Hal ini mengharuskan dilakukannya upaya perbaikan tanah lunak agar bisa dijadikan lahan bangunan nantinya. Adapun pada metode yang akan dilakukan pada perencanaan ini menggunakan kombinasi metode preloading dan PVD untuk mempercepat proses penurunan tanah. Berdasarkan hasil perencanaan didapatkan total tinggi timbunan (preloading) adalah 3,5 m dan waktu perencanaan berlangsung 4 bulan. Perbaikan tanah lunak dilakukan sampai dengan kedalaman 25 m dengan desain PVD menggunakan pola segitiga dan spasi 1,3 m. Penurunan konsolidasi 95% akibat beban timbunan menyebabkan tanah turun sedalam 1,928 m. Pada perencanaan ini menggunakan pemodelan Plaxis 8.6 2D dan hasil penurunan tanah yang dihasilkan adalah sedalam 1,990 m.

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Study on the horizontal bearing characteristics of pile foundation in coral sand

Canadian Geotechnical Journal ◽

10.1139/cgj-2020-0623 ◽

2021 ◽

Author(s):

Chunyan Wang ◽

Hanlong Liu ◽

Xuanming Ding ◽

Chenglong Wang ◽

Qiang Ou

Keyword(s):

Lateral Displacement ◽

Experimental Studies ◽

Deformation Characteristic ◽

Bending Moment ◽

Silica Sand ◽

Pile Head ◽

Pile Diameter ◽

Coral Sand ◽

Horizontal Pressure ◽

Different Diameters

This paper presents the horizontal bearing characteristics of piles in coral sand and silica sand from comparative experimental studies. A total of 6 model piles with different diameters are tested. The horizontal bearing capacity, deformation characteristic, bending moment, p-y curve, the change in soil horizontal pressure, as well as the particle breakage behaviour of coral sand are investigated. The results show that, in coral sand foundation, the horizontal bearing capacities of piles and the increments of soil horizontal pressures are obviously greater than those in silica sand. Accordingly, the lateral displacement, the rotation of pile head, the bending moment and the corresponding distribution depth in coral sand are significantly smaller than that in silica sand. The p-y curves indicate that the horizontal stiffness of coral sand is greater than that of silica sand. Remarkably, the breakage behaviour of coral sand is mainly distributed in the range of 10 times pile diameter depth and 5 times pile diameter width on the side where the sand is squeezed by pile. Furthermore, in coral sand, the influence of pile size is more pronounced, the squeezing force generated by pile spread farther and its influence range is larger compared to those in silica sand.

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coral sand

Dictionary Geotechnical Engineering/Wörterbuch GeoTechnik ◽

10.1007/978-3-642-41714-6_34869 ◽

2014 ◽

pp. 295-295

Keyword(s):

Coral Sand

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Mechanical Properties and Microscopic Mechanism of Coral Sand-Cement Mortar

Advances in Materials Science and Engineering ◽

10.1155/2020/4854892 ◽

2020 ◽

Vol 2020 ◽

pp. 1-11 ◽

Cited By ~ 1

Author(s):

Luoxin Wang ◽

Junshuai Mei ◽

Jing Wu ◽

Xingyang He ◽

Hainan Li ◽

...

Keyword(s):

Mechanical Properties ◽

Cement Mortar ◽

Mineral Admixture ◽

Mineral Admixtures ◽

Hardened Cement ◽

Hydration Reaction ◽

Microscopic Mechanism ◽

X Ray ◽

Volume Stability ◽

Coral Sand

The workability and mechanical performance of coral sand-cement mortar (coral mortar, for short) and the modification effects of mineral admixtures on the coral mortar were studied in this paper. The results showed that the strength of coral mortar was lower than that of standard mortar, but the strength of coral mortar was improved by compositing with the mineral admixture, which can be attributed to the improvement of the microstructure and interface transition area. Scanning electron microscopy (SEM), energy dispersive X-ray spectroscopy (EDS), X-ray diffraction (XRD), and Fourier transform infrared spectroscopy (FTIR) were used to explore the microscopic mechanism involved in the mechanical properties, volume stability, and hydration of mortar. The analyses revealed that the internal curing effect of coral sand improved the mechanical properties of mortar and its ability to resist shrinkage. The uneven surface of coral sand formed a meshing state of close combination with the hardened cement mortar, which helped to improve the volume stability of mortar. The Ca2+ and Mg2+ ions from coral sand participated in the hydration reaction of cement, which contributed to generating more hydration products. Moreover, the microaggregate filling and pozzolanic effects of fly ash and slag improved the mechanical properties of coral mortar and resistance to chloride ion diffusion.

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