Hydraulic fracturing is frequently applied in the petroleum industry as a method of reservoir stimulation, and appearing to have useful environmental and geotechnical applications. The contaminants may be widespread to pollute larger area by the unintentionally formed hydraulic fracture. The injection of grout, in-situ permeability test, recharging of ground water, dam construction, etc., are the main causes forming the hydraulic fracture, only if the pressure using in the process is not properly controlled. In the present study, attempts have been paid in defining the effects of hydraulic fracture on the engineering properties of sand-bentonite mixture, which is often used as hydraulic barrier in the construction of earth dam, as the lining of waste disposal unit. In summary, hydraulic fracturing involves the injection of fluid (water) in to cylindrical blocks of compacted sand-bentonite mixture, under over burden pressure designed, at a rate that is sufficient to initiate a fracture. A fracture cell is a hollow steel section (inside diameter 30 cm) which upper movable side used for loading. The pressue of 50 kPa was used for loading. The pressure of 50 kPa was used for vertical permeability tests. The coefficient of permeability, of sand and sand bentonite mixture, kv is 10 -6 - 10 -7 and 10 -8 - 10 -10 m/s, respectively. Under over burden pressure is 100, 250 and 400 kPa, ratio of hydraulic pressure to overburden stress is 1.0 in 8, and 10% bentonite, and more than 1.6 in 12% bentonite. However, rate of hydraulic fracture to induce hydraulic fracture in 14% bentonite, under overburden pressure 100 and 250 kPa is 300 kPa. The other engineering properties such as undrained shear strength, deformation characteristic, maximum dry density have been tested.
