trench wall jack: an apparatus to measure the equivalent elastic modulus of soil

the modulus of elasticity of soil is required for many applications, and can be used in attempting to predict the magnitude and distribution of deflections, wall stresses and strains imposed by soil loading on buried pipelines. this report describes a 'trench wall jack' which can be used to determine the load deformation characteristics of in-situ soil at the side of a trench. circular plates are loaded against opposite sides of a trench by means of a hydraulic jack. the load and penetration are measured by suitably placed transducers and the output of these transducers is recorded on an x-y plotting machine. an equivalent modulus of elasticity for the soil can then be calculated from the results. the apparatus and the testing techniques used are described and the results of the tests carried out with a remoulded cohesive soil are given. in these tests, the modulus determined by this apparatus was comparable with those obtained from undrained triaxial tests, but the results were more consistent.(a)