Reasons of ground heaving during pipe-jacking

It is commonly recognized that ground settlement is one of the significant concern in pipe jacking operation. Though engineer must also pay attention to the problem of ground heaving at the time of grouting work of pipe-jacking. For illustration, if excessive slurry or grout pressure is applied so as to exceed overburden pressure, ground heaving would result. Otherwise if the ground contains loose soils with high porosity, same phenomenon also takes place. Proper control on the applied pressure and viscosity of slurry/grout is essential to prevent such occurrence.