The existing soil does not always have enough bearing strength to support structures above it. The failure of soil to maintain its stability subject to load can result a great impact to the structure. Various methods have been implemented over the years, there are compaction, vibroflotation, precompression, sand drains, soil stabilization using chemicals, use of stone columns and granular trenches, use of geogrids, use of geotextile, etc.

Case Study : Soil Improvement in Swampy Area of PT. Exspan Nusantara
at Rimau Block in South Sumatra

Joi Surya Dharma
Project Management Department – Kaji Area

Abstract

The existing soil does not always have enough bearing strength to support structures above it. The failure of soil to maintain its stability subject to load can result a great impact to the structure. Various methods have been implemented over the years, there are compaction, vibroflotation, precompression, sand drains, soil stabilization using chemicals, use of stone columns and granular trenches, use of geogrids, use of geotextile, etc. The problem is that different soil condition needs different soil treatment or a combination of several methods, since every method has its own advantages and disadvantages over others. This paper analyses the process to select the most appropriate method to improve the soil condition in swampy area from many aspects such as the technical, implementation procedure, and cost effectiveness aspects.

1. Introduction

Soils are used extensively in and with many types of construction. They are used to support structures, to support road pavements, etc. Some soils may be suitable for use in their natural state, while others must be improved in order to serve their purposes. One of the examples the soil that needs to be improved is the soil in swampy area.

Indonesia has one of the largest land areas of swamp in the world; estimates of the total area vary between 19 and 26 million hectares (ha) with 8 million ha of swamp over 2 m deep (Euroconsult, 1984). A substantial part of these swamp deposits are found along the east coast of Sumatra and Kalimantan, an area now being developed as a result of oil and gas finds.

PT. Exspan Nusantara (PTEN) is one of the many oil and gas companies that has operations in those swampy areas. If we do not take a full anticipation action then this problem most likely will ruin the entire project. This problem is greatly faced during project construction development which may include but not limited to the construction of roads, right of way (ROW) of pipeline, access to wellheads, hardstands for drilling rig, camps, facility and other uses.

In this paper, types of soil and the purpose of soil improvement are explained to give a basic understanding to the reader, then various methods are explained in brief include all aspects that taken into consideration. Case study in the Rimau Block is explained next by using problem solving and decision making process flowchart that author applied for this paper. The detail explanation of technical, implementation procedure and cost effectiveness of selected method is further explained in here. At the same time, it expresses its confidence for this labor-intensive method to contribute to relieve social problems resulted from increases in number of jobless people under the current economic crisis.

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