Ground Improvement By Controlled Modulus Columns—A West Africa Case Study

Ground Improvement Techniques serve to improve engineering properties for supporting various foundations. These may be undertaken either by conventional or advanced methods. The Controlled Modulus Column (CMC), also known as Rigid Inclusion, is a soil improvement technique to reduce the total and differential settlement by using semi-rigid soil reinforcement columns. The CMC technique can be executed by displacement or non-displacement methods. It does not aim to bypass the compressive layer or to instal a pile that will directly support the entire load from the structure. The principle of the technique is to introduce a load transfer platform between the head of the column and the structure, and transform a uniform load into the soil. Initially, the structural load transmitted into the soil generates a settlement greater than CMC piles. When the settlement between the soil and column became equal at the neutral point, the maximum structural load shall be balanced by the positive friction and tip resistance to stabilize the foundation without exceeding the allowable settlement limit. This paper describes the behaviour of soil reinforcement with CMC and their installation process with reference to a project at the Dry Bulk Terminal Port at Western coast of Africa. The methodology of CMC, requirements of Ground Improvement, arrangements and outcome of this method are presented in this paper.