A thesis submitted m partial fulfillment of the requirements for the degree of Master of Engineering, School of Civil Engineering

Thesis (M. Eng.) - Asian Institute of Technology, 1996

Pullout and large scale direct shear tests were conducted on hexagonal wire meshes embedded in four different fill mat~rials namely lahar, sand, gravel and lateritic soil. Two types of wire meshes were tested, one is galvanized having a small aperture with cell size dimensions of 8 cm x 6 cm, while the other is also galvanized with additional PVC coating having larger aperture with cell size dimensions of 10 cm x 8 cm. Each type have a 2. 7 mm inner core wire diameter made of high strength steel. The tests were conducted at four different normal pressures ranging from 2. 5 to 10 ton/m2 and pulled or sheared at a rate of 1 mm/min. These were done to investigate the interaction between reinforcement and soil, and determine the pullout resistance of each type of reinforcement in various soils. The test results show that galvanized wire meshes generally have greater pullout resistance by comparison with PVC coated wire meshes. Also, normal stress, soil confinement and soil particle size have influence on the pullout strength. Direct shear tests yielded direct sliding coefficients of 0.9 to 1.0 for frictional fill materials and 0.7 to 0.9 for cohesive-frictional fill materials for both types of meshes. These tests lead to the formulation of design procedures for hexagonal wire mesh reinforced MSE walls. The study was done to provide an alternative solution to the lahar problem currently experienced in the northern provinces of the Philippines brought about by the eruption of Mount Pinatubo.