In specific urban areas and even nations the interest for land and space is quickly surpassing the supply. Sea centers don’t escape from this reality, the persistent extension of business sea movement and exercises in seaports because of increments in universal exchanging has produced an expanded interest for a viable utilization of ports and harbors. Development exercises have been situated to the extension of existing offices
Port and harbor offices frame the foundation that makes marine movement conceivable, encouraging the development of vessels, its security against wave activity and, its stacking and emptying exercises. At the end of the day, they assume an essential part in encouraging worldwide trade.
The various types of marine works and harbor constructions in which these caissons can be utilized are:
- Berthing Facilities and Docks
- Dry Docks and Slipways
- Fishing Ports and Marinas
Construction of Hand-dug Caisson
Hand-dug Caisson refers to the one of the piling techniques in the past, but, now it is banned in Hong Kong. Thus, there are a few things we ought to know about it.
Step 1: Installation
- specify the caisson position and size.
- dig up one meter into ground.
- put up caisson lining steel form.
- Concrete caisson lining.
- put up the digging platform on apex of caisson centre.
- take apart caisson lining steel form on another day.
- conduct step 2 to 6 (except step 5) until time of bedrock.
- Dig up bellout into bedrock till requisite level.
- Set up caisson reinforcement.
- tidy up caisson bottom.
- put in concreting chute.
- Concrete caisson heart till the desired level.
Step 2: Preventive measure
For stabilizing any unhinged levels of subsoil which could be met at the time of caisson excavation and avoid unnecessary settlement to the adjacent building/pavement because of effect of dewatering, grouting refers to one of techniques which could be taken as a precautionary evaluation before caisson excavation.
Step 3: monitoring
- To make sure that there is no adverse effects forced on the adjacent structures throughout caisson construction, the subsequent preventive procedures and limiting criterion, to be regulated all the way through the construction period, are suggested.
- The layers of checkpoints have to be controlled frequently and the calculated resolution of building structures and road pavement should not be more than 10 mm and 25 mm correspondingly.
- Standpipes piezometer have to be installed prior to the caisson excavation for monitoring of the ground water table drawdown which should not be exceeding the specific value at any cost.