Study on variation of vertical additional force on shaft lining by simulation tests

The simulation tests were carried out to study the variation of the vertical additional force acted on shaft lining by surrounding soils during dewatering of alluvium by means of multi-function rig in vertical shaft.On the basis of the analysis of the test data,the additional force linearly increased with variation of water pressure in the aquifer,and increased with the increase of the depth and with the content of coarse soil particle in the overburden layer.According to calculations,it was necessary to adopt a new type of structure of the shaft lining with vertically yieldable segments for reason of safety.