Hi Davis , I understand the ...

Hi Davis , I understand the problem facing by you ,you need the caisson well water tight as well as as proof make the construction to sustain the earht pressure and surrounding water logging thrust. My advice to you that start the process or work in link methods. 1] first do the precast for the caisson well in various number for a height not more than 1.0 mt . 2] Do the excavation and pumping in simultaneously ,so as to put the members of precast caisson well and fixing it in joint make the joint water and gas tight by silicon or PVC fluid. 3] while excavation work and arrangement of precast member put multiple no of oxygen cylinders and exhaust system so as make feasible to circulate the oxyegen as well to remove the foul gases. 4] In the mean time after every four hours change the shift of labour teams alloted for precast fixing members , excavation ,pumping and concealing the precast . 5] It will take time but the target needs to achieve can be done in very perfect manner and without any accident or casualties. If needs more guidance you can mail me also. sanjay.chandne@yahoo.com