A Study on the Engineering Behaviour of Grouted Alluvial Soil

Authors: Ganga Sagar Singh, Anoop Sharma

Country: India

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Abstract: Alluvial soils are widespread in the northern plains and river valleys. It covers about 40% of the total area of the country. These soils are mainly derived from the debris brought down from the Himalayas.

In the Peninsular region, they are found in deltas of the east coast and in the river valleys. Alluvial Soil is also called as Alluvium.

Alluvium (derived from Latin word alluvius) is loose clay, silt, sand or gravel that has been deposited by running water in a stream bed, on a floodplain, in an alluvial fan or beach, or in similar settings. Alluvium is also sometimes called alluvial deposit. Alluvium is typically geologically young and is not consolidated into solid rock. Sediments deposited underwater, in sea, lakes, or ponds, are not described as alluvium.

This type of soil profile is very common in areas of Jammu & Kashmir, especially in Akhnoor Area of Jammu district. Further, the high water table and limited depth of the top sandy layer in these areas restrict the depth of foundation thereby further reducing the safe bearing capacity.

The present investigation was aimed at obtaining solutions for problems like this. The improvement in relative density and thereby the load carrying capacity of loose sandy soils of different gradations through different methods such as vibration technique was studied. The low values of bearing capacity estimated even after densification compared to the requirement in the case of foundations for multi-storey buildings or structures of highways/roadways prompted to try grouting as one of the possible solutions.

Grouting is quite a familiar term in foundation engineering, the primary purpose of which is to fill the voids of the formation material by replacing the existing fluids/air with the grout and thereby improving the engineering properties of the medium. The most commonly used grout material i.e. - ordinary Portland cement - has many advantages such as high strength, high durability, environmentally free and of low cost. Two methods were adopted to place the grout within the pores of the sand medium. They are: (1) by hand mixing the grout uniformly with the soil, and (2) by mixing the filter media with the soil.

The effect of cement grouts on the shear strength and the shear strength parameters of loose sandy soils were investigated. The effect of the common admixtures used along with cement grouts (accelerators, retarders, fluidiser, antibleeders, etc.) on the shear strength of the grouted medium was also studied.

A grouting setup was developed in the laboratory for grouting the sand beds prepared in mould or will choose a particular site of NH144A Jammu to Akhnoor ongoing work. The lateral flow of the grout and thereby the efficiency of grouting was assessed by three methods (1) from the cross section area of the grouted mass measured at different depths, (2) by determining the cement content at different radial distances at different depths, and (3) by conducting load tests on the grouted sand beds.

The effectiveness of grouting in reducing the permeability of granular medium was also studied. Constant head permeability tests were carried out on the sand medium treated with different materials such as cement, bentonite, lime, locally available clay and different combinations of the above materials.

The results of the various investigations conclusively proved that grouting can be used as an effective method for improving the strength characteristics significantly and reducing the permeability of loose sandy soils.

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Paper Id: 230121

Published On: 2023-05-16

Published In: Volume 11, Issue 3, May-June 2023

Cite This: A Study on the Engineering Behaviour of Grouted Alluvial Soil - Ganga Sagar Singh, Anoop Sharma - IJIRMPS Volume 11, Issue 3, May-June 2023.

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