Design Criterion of Reinforcement on Thick Soft Clay Foundations of Traditional Construction Method in Indonesia

Abstract

It is commonplace that the ground near river is thickly covered with soft clay. Thus, in order to prevent it from the natural hazard, it is necessary that local people construct a robust embankment of countermeasure by constructing river bank in the soft ground, with low level of bearing capacity. To solve the problem aforementioned, local people are widely known to apply traditional method such as timber or bamboo pile. To establish this method, the Ministry of Public Works has published a technical guideline for reinforced soft ground before embankment. The guideline shows the process of mattress construction including: 1) cutting the ground for site preparation; 2) installing timber piles; 3) laying geo-grid on top of the piles and; 4) putting and compacting a granular material on the geo-grid. The guideline assists engineers to construct an embankment on the mattress. Unfortunately, the guideline never details a reasonable design based on geotechnical engineering. Hence, this paper aims to propose and discuss, a criterion of bearing capacity of reinforced soft clay using several empirical calculations. The model cases were simulated for small footings subjected by static loading on the mattress. As a result, the calculations will lead to the criterion of allowable bearing capacity of reinforced soft clay with timber pile.