CONSTRUCTION OF EARTH FILL STRUCTURE FOR SMALL FARM POND BY USING BHUTANESE TRADITIONAL WALL MAKING METHOD

Abstract

The Kingdom of Bhutan has mountains as high as 7,000 meters height at the east end of the Himalayas and the semitropical region at an altitude of 100 meters in its south area. Because of its precipitous terrain, stable supply of water for irrigation is difficult without efficient water supply system such as reservoirs, pipelines and so on. Based on the results of preliminary field investigations, existing reservoirs in the Kingdom of Bhutan often have structural problems in its body and foundation. To contribute to an increase in agricultural production in the Kingdom of Bhutan through the development of construction techniques for reservoirs, an earth fill structure for a small farm pond was suggested and constructed in 2015. In this construction, the Rammed earth method, which is well known as a Bhutanese traditional wall making method, was applied as a compaction technique of soil. Authors conducted a follow-up of the earth fill structure in September 2017 to confirm the performance of the wall making method as a construction technique for reservoirs. Based on the results of the portable dynamic cone penetration tests, it is supposed that this rammed earth method couldn’t achieve sufficient compaction energy for construction of earth fill structures for reservoirs because observed N values were comparatively small compared with that obtained from embankments constructed by modern compaction techniques. Therefore, in the construction of earth fill structures for farm pond by utilizing the rammed earth method, improvement in the compaction technique should be considered.