EXCAVATION FOR BASEMENT / FOOTING / TRENCHES

Excavation work

Excavation work

Excavation work

Excavation work

 EXCAVATION FOR BASEMENT / FOOTING / TRENCHES

1.    OBJECTIVE:

The objective of this method statement is to carry out the Excavation works by meeting the technical specification and complying with Standards.

2.     SCOPE:

The scope of this method statement includes at all areas at CTSIL, CTSIL site while executing it in accordance with Technical specifications.

3.    REFERENCE 

·         IS-Codes

·         Technical Specification

4.    TOOLSAND TACKLES

·         Trowel,

·         Total Station,

·         Excavator,

·         Tipper,

·         Line Dori,

·         Plumb bob,

·         Measurement tape,

·         Pegs,

·         Pencil,

·         Spade,

·         Hammer,

·         Brushes and buckets,

·         Right angles,

·         Dewatering Motor

5.    MATERIAL USED:

·         Excavator

·         Gondolas

6.    PROCEDURE:

a)    General:

·         Ensure Material approval prior to start work

·         Ensure cleaning to be done properly.

·         Ensure necessary safety precautions are in place prior to start.

 

b)    Sequence of Work:

·         Before starting the excavation work Built-up area, clearing of shrubs, bushes, vegetation and cutting of trees to be done.

·         Setting out the control points of the building.

·         Establish Temporary Bench Marks (TBM) all round the site. Locations are decided based on visibility and permanency of TBMs. Write the Reduced Levels (RL) on the TBM. R grids of 3m may be required for greater accuracy.

·         Take grid level before the start of mass excavation, if the terrain is slopping or rolling, close 

·         Excavate in a phased manner after proper setting out of works.

·         Excavation boundary marked with 6000mm offset from footing edges which includes 150mm offset of Block work and rest as working space 

·         If required, keep dewatering pumps available and discharge point accessible. Keep necessary information regarding water table, periods of rainfall and flooding of site and so on.

·         Shore slopes or step cut the sides as you excavate below 2 meters to ensure stability of sides.

·         Use appropriate machinery. This will ensure minimum idling time of equipment.

·         Depth of excavation is to be constantly monitored with Total Station in relation to the TBM located around the site.

·         If excavation is carried out to a greater depth than specified, extra depth shall be filled with 1:4:8 ordinary grade concrete rammed in position until it is brought up to the specified level. 

·         Re– handling of excavated earth is costly and should be minimized.

·         Site Engineer should inspect the site after the required depth of excavation is achieved. Immediately after inspection the bottom level of excavation is treated with termites and sealed with Lean Concrete.

·         Proper arrangement for dewatering should be made whenever the excavation during the raining periods.

     

a)    Inspection methodology

·          First check if the approved site plan with setting out details exists.

·         The checks that need to be made before work starts include the stability and levels of the original ground or foundations at the base or top of embankments, selection of suitable fill material and the stability and profiles of side slopes.

·         Marking in conformance as per drawings. The centre line should be checked.

·         Ensure that correct area is excavated properly including the depth, length and breadth of the site using Total station as per drawings. Checking of levels (random) using Total station.

·         Ensure any loose patches of soil are properly dug out and filled and rammed with 1:4:8 ordinary grade concrete.

·         Wherever the depth of trench is more than 2 meter, barricading all around the excavated site at a distance of one meter from the circumference.

·         If the slope of the excavated earth has a gradient more than 60 degrees , then ensure that the stepping/terracing is done to avoid any caving in of earth due to landslides.

7.    RESPONSIBILITIES.

·         Construction Manager: He shall be responsible for overall management of construction activities.

·         Site Engineer: He shall be responsible for Executing in safe work method as per drawings and guide the supervisors and work men.

·         Site Supervisor: He shall be responsible managing all plant, machineries, labour, and safety of the workers.

·         QA/QC In charge: He shall be responsible for ensuring the quality of work as per the specifications and standards.

·         HSE Manager/Engineer: He shall be responsible for assisting to engineer/supervisor to ensure the safety of workers during the progress of work. Safety inductions of each staff and workers shall be done and daily PPE check to be done and tool box talk shall be carried out before the start of work. General safety awareness as well as particular safety precautions and guidelines for activity to be carried out in that particular day shall be discussed.

·         Stores officer: He shall be responsible for storing of all materials. Also responsible for maintaining the record of incoming and outgoing and up to date stock details of materials.