2.1 Dimension and length of temporary steel casing
The diameter of the temporary steel casing minimum is 35 cm. The length of each temporary casing is 1.2 meters. Each casing will be connected and secured by coupling system. The casing will be drilled and lowered into soil by the cylindrical hammer. During the drilling process, soil will be removed through center core of casing. Once the designed depth is reached, reinforcement cage will be installed into the bored hole.
2.2 Drilling process
During drilling in the soft-soil layer, the hole will be drilled into soil using the steel bucket (which can collect the soil by its weight). Soil will then be collected in the bucket. This process will be continued until the bucket is full, and soil will then be dumped outside drilling hole. The process will then be continued until the casing is drilled to the medium-hard soil level. The bucket will then be used continued to the designed depth.
2.3 Inspection of borehole before lowering rebar casing
a) Measurement of depth
The depth of borehole will be measured using the special measuring steel tape.
b) If there is seepage in the pile base, dry mixed concrete in the ratio of 1:2:4 (in the amount of 30-40cm) will be placed.