Shear resistant drain system for improving weak foundation soils

A method of preparing ground to receive a static load in which the ground includes a weak soil layer consisting of fine grained soil particles over a base layer and in which the static load defines a shear plane within the weak soil laver, the method comprising:

• providing a plurality of pipe members, each pipe member being elongated and including a hollow interior and a plurality of openings therein;
• providing a reinforcing member extending about each pipe member so as to provide tensile reinforcement at least in a circumferential direction about each pipe member;
• inserting each pipe member in an upright orientation within the fine grained soil particles of the weak soil layer such that fluid can readily pass through the openings in the pipe members from the fine grained soil particles surrounding the pipe members into the hollow interior of the pipe members;
• and
• providing aggregate fill occupying the hollow interior of each pipe member such that each pipe member with the reinforcing member thereon and the aggregate therein collectively defines a shear drain device that (i) traverses the shear plane associated with the static load to increase a shear strength of the fine grained soil particles within the weak soil layer and (ii) dissipates excess porewater pressure within the fine grained soil particles resulting from the static load.