4　Foundation

4.1　Earthwork and Foundation Pit

4.1.1　When the chimney excavation is ready，the constructor，jointing with the owner，designer and supervisor，shall inspect the excavation center coordinates，foundation bed dimension，elevation and levelness，to identify whether the design requirements are reached，also the soil of foundation bed whether satisfies the soil investigation report the design referred.When it is not satisfied，the owner and designer shall propose solutions.

4.1.2　When the excavation bottom is below the groundwater table，based on the hydrologic and geological conditions，lowering and drainage work shall be taken prior to the excavation works.Also the groundwater table shall be maintained below the lowest elevation of the working field.Meanwhile，measures shall be taken to prevent surface water flowing into the excavation.The continued lowering or drainage work shall not be ceased until the filling soil is backfilled above the groundwater table.

4.1.3　The natural soil surface of the excavation bottom shall be flat.It is prohibited to level it with filling.

4.1.4　After the excavation is accepted，the foundation construction work shall commence in a timely manner.When there is a longer interval，the excavation shall be re-inspected prior to the construction.For individual recessing positions that are below the design elevation，may be leveled with blinding concrete.When the bottom soil is disturbed or immersed by water，it shall be totally removed，and the blinding layer shall be constructed higher to reach the design elevation.When the bottom soil is seriously damaged，the constructor，designer and supervisor shall determine the appropriate remedial action.

4.1.5　When foundation construction work is finished，the acceptance and backfill work shall be taken in a timely manner.The filling soil shall be compacted in layers.The compaction factor shall meet the design requirements.When there are no design requirements，the compaction factor shall not be less than 0.92.