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RESEARCH ARTICLE-CIVIL ENGINEERING

Cyclic Behaviour and Durability Analysis of Sand Grouted with Optimum Colloidal Silica Content Jiji Krishnan1 · Prashansha Sharma1 · Shruti Shukla1 · Vasu Pancholi2 · Vinay Kumar Dwivedi2 Received: 17 September 2019 / Accepted: 14 May 2020 © King Fahd University of Petroleum & Minerals 2020

Abstract The main objective of the current research is to study the dynamic behaviour of colloidal silica treated grout. The treatment of foundation soil with colloidal silica improves the cyclic strength of the soil, which has the potential to reduce damages in buildings during earthquakes. Cyclic triaxial tests were conducted at various double amplitudes to understand the cyclic resistance of the colloidal silica grouted sand. The test results of untreated samples at different relative densities were compared with the treated samples having the same relative densities. The present study revealed that the optimum percentage of colloidal silica decreases with an increase in relative density. The grout inside the treated area would undergo geothermal and water table changes. Wetting and drying cycles were studied to understand the durability of the above-mentioned grout. The samples sustained 18 wetting and drying cycles which in turn proves its superior durability characteristics. It was observed that the confining pressure, total energy capacity, as well as brittleness index and colloidal silica percentages, are some factors determining strength characteristics. Furthermore, the addition of colloidal silica in sand improves the cyclic resistance strength, damping ratio, and the shear modulus. Keywords Colloidal silica grout · Cyclic triaxial tests · Durability · Soil stabilisation · Liquefaction mitigation

1 Introduction Soil stabilisation is a technique to improve soil’s mechanical properties in order to meet engineering requirements. In liquefiable soils, stabilisation is generally done to limit settlements and increase liquefaction resistance [1]. Conventional soil improvement techniques such as soil replacement, vibration compaction, deep mixing pile method, lowering of the groundwater table have some significant drawbacks. These methods limit the area of site treatment which disturbs the existing structures. Also, most of the grouting materials pose a threat to the environment [2]. Grouting is considered to be a successful ground stabilisation method [3–5], which in turn helps to mitigate liquefaction and increases the shear strength. Shear strength is essential as well as a complex parameter which has different values under different field and engineering conditions. Liquefaction induces

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Jiji Krishnan [email protected]

1

Sardar Vallabhbhai National Institute of Technology, Surat, India

2

Institute of Seismological Research, Gandhinagar, India

shear stresses in sandy soils during earthquakes due to the generation of excess pore water pressure. Thus, the subsoil softening during liquefaction damages the structures as well as foundations. Moreover, if the shear strength of the s