News Detail

Bore Pile Works PLTU Sumbagsel-1

24 / 12 / 2022 - Press Release

Bore Pile Works

1. Implementation of Drilling Work

The preparatory work is the stage of determining the drill points, determination of drill points based on the planned foundation plan drawings. In addition to determining drill points, auxiliary points are also determined which are useful for installing temporary casing in drilling with a boring tool. The next process is that the implementer and the drill machine operator will inspect the ground around the drill point and then install a platform (plate) for the drilling machine to stand on, then the drilling machine and drilling equipment such as auger buckets, cleaning buckets, and others are moved to the planned location. After that, the position of the drilling machine is adjusted so that the position is horizontal.

This initial drilling was carried out to a depth of 2 meters. As a guide for the operator to find out the position of the drill point, a coordinate tool is used, which is usually found on a drilling machine. After the initial drilling, then a temporary casing was installed with the help of a crane to adjust the position of the casing, this temporary casing is equipped with two holes on the left and right which function as the crane hook entry.
Continued drilling according to the plan in the drawing.
After the temporary casing is installed, then drilling continues to the depth according to plan.


2. Rebar Frame Work

In the manufacture of bending spiral iron reinforcement using an electric bending tool. Rebar frame is useful as reinforcement from Bore Pile which is made with the main diameter and amount of steel reinforcement. The spacing of the spiral steel is in accordance with the plans for each drilled pile. The binder between the main iron and spiral iron uses concrete wire (bendrat).

Making the rebar frame starts with installing concrete spacers with a maximum distance of generally 3 meters and a minimum number of 3 per circle. As a strengthening effort, welding was carried out on the iron basket. Welding is carried out on the main reinforcement with spiral reinforcement so that when it is lifted by a crane and attached to the hole so that the cut of level frame is not destroyed. The finished rebar frame is then estimated at its lifting point, approximately 1/3 of the length of the iron basket. Furthermore, the rebar frame is lifted using a crane and stored in a storage area for later use in rebar frame installation.

3. Installation of Rebar Frame

After checking is complete, the iron basket is moved near the drilled hole and placed on a pedestal so that the iron basket does not touch the ground. The removal of iron baskets must also be careful in order to reduce the deformation that occurs so as to simplify the installation process. If the rebar frame is more than 12 meters to make work easier it is made into two sessions. Using a crane, the first rebar frame is inserted into the drilled hole. With a certain depth by hooking the slings and shackles at the lifting point of the rebar frame which has been calculated beforehand.

After the first rebar frame enters the hole, it is then propped up by hooking it to the casing. The next step is to lift the next rebar frame using a crane and place it on top of the first rebar frame that has been propped up before. Then do the connection between the first rebar frame and the second rebar frame by using welding. After the two rebar frames are connected, the rebar frame is then lowered again until it reaches the design depth, then the top of the rebar frame is reattached to the casing which is used to hold the rebar frame at the desired depth for further concrete casting work.

4. Casting Concrete

Preparation of tools to be used for casting must be carried out like preparing tremie pipes. So that the fresh concrete can flow properly in the drilled hole to be cast, also prepare the crane locking bolts so that when lifting and connecting the tremie pipe is more time efficient.

Tremie pipe installation must be done carefully and in such a way as to reach the planned soil depth. It should be noted that the tremie pipe connection must be watertight so that the concrete to be cast flows in the pipe properly.
A slump test needs to be carried out before starting casting, so that the concrete specifications are as desired.

After the tremie has been installed in the drilled hole, before starting casting concrete on each concrete mixer truck, 3 samples are taken first which are printed on a cylindrical mold, which later these samples will be tested for their compressive strength.

After the casting is complete, the temporary casing is removed by connecting the holes on both sides of the casing with a lock on the crane, then lifting it carefully so that the casing does not tilt when it is removed, and the Bore Pile casting concrete process is complete.