Method Statement for Excavation WORK

METHOD STATEMENT
FOR
Excavation works
Table of Contents

1. PURPOSE ------------------------------------------------------------------------------------------- 2

2. SCOPE ----------------------------------------------------------------------------------------------- 2

3. RESPONSIBILITIES ------------------------------------------------------------------------------ 2

3.1 Project Manager -------------------------------------------------------------------------------------------------------------------------- 2

3.2 Station Manager -------------------------------------------------------------------------------------------------------------------------- 2

3.3 Site Engineer ------------------------------------------------------------------------------------------------------------------------------- 2

4. DEFINITIONS --------------------------------------------------------------------------------------- 3

5. REFERENCES -------------------------------------------------------------------------------------- 3

6. METHODOLOGY: --------------------------------------------------------------------------------- 3

6.1. Traffic Diversion----------------------------------------------------------------------------------------------------------------------- 3

6.2. Utility Diversion ----------------------------------------------------------------------------------------------------------------------- 4

6.3. Monitoring and Instrumentation ------------------------------------------------------------------------------------------------ 4

6.4. Excavation ------------------------------------------------------------------------------------------------------------------------------ 4

6.5. Examination of Exposed Diaphragm Walls------------------------------------------------------------------------------------ 5

6.6. Temporary stockpile and disposal of excavated materials--------------------------------------------------------------- 5

7. SAFETY ---------------------------------------------------------------------------------------------- 6

8. QUALITY --------------------------------------------------------------------------------------------- 6

9. EQUIPMENTS -------------------------------------------------------------------------------------- 7

10. ATTACHMENTS -------------------------------------------------------------------------------- 7

Page 1 of 13
Method Statement for Excavation WORK

1. PURPOSE
This document covers Method Statement for Excavation works, in order to carry out the works in planned
and systematic manner.

2. SCOPE
This method covers following activities:

 Excavation to the lines & levels shown in drawings

 Disposal of materials
 Installation of dewatering system(if any) for keeping excavation free from water
 Monitoring & instrumentation for ground water level, settlement, deflection, movement etc

3. RESPONSIBILITIES
3.1 Project Manager

 The approval of this MS

 Overall scope of work.
 Coordination of personnel and equipment to ensure continuous program of works during
execution.
 Receiving daily progress reports and distributing to Client’s approved representative and
Contractor’s Management, and ensuring prompt action to any matter highlighted in the
same.

3.2 Station Manager

 Implementation of this MS.

 Safety to personnel, incident reporting and implementation of the Safety Management Plan
and Safety Management System.
 Ensuring that the works are carried out in accordance with approved permits and MS.
 Ensuring that all personnel are fully aware of their duties and responsibilities.
 Liaising with Client’s approved representative during the operations and during MS change,
contingency operations or mitigation works.

3.3 Site Engineer

 Ensuring construction is in accordance with approved MS and specifications.

 Ensuring that all data is recorded in accordance with this document.
 Ensuring all required as built data are recorded.
 Providing any information and field calculations that may be required during the work.

Page 2 of 13
Method Statement for Excavation WORK

4. DEFINITIONS
For the purpose of this document the term:

 JKIL : Contractor
 QA : Quality Assurance (applies essentially to process)
 QC : Quality Control (applies essentially to works and products)
 ITP : Inspection& Test Plan-A document that sums up all the
information related to inspections, measurements and tests
to be carried out during execution of work in scope. For the
scope, the term ITP is used.
 Shall : Mandatory Requirement
 Should : Recommended Practice
 SHEVC : SHE verification checklist

5. REFERENCES
 Applicable Specifications - refer to Attachment 1
 Applicable Project Procedures - refer to Attachment 1
 Applicable Project MSs - refer to Attachment 1
 Applicable Drawings & Sketches – refer to Attachment 2

6. METHODOLOGY:

6.1. Traffic Diversion

Hoardings shall be erected and the traffic diverted in accordance With the approved traffic
diversion plan. All signages and other provision to be carried out in accordance With this Method
Statement and latest approved signage plan. Furthermore, this section shall identify specific exit
and entry points for the dump truck. These shall be clearly identified and manned by signal men
and free flow of dump truck on the public highway.

Prior to excavation the following shall be ensured.

 A continuous rigid guard rail &hard barricading with top & mid board arrangement shall be
provided. Toe wall of 150mm height shall be made around opening for excavation works.
Sand bags shall be kept around openings for protection during excavation.
 A centralized access shall be provided at a specific point for the entry of Workmen and
equipment’s with proper checking of Identity card etc. by deployed security personnel. Site
Layout plan depicting the Wheel wash facility shall be displayed at exit gate. During
excavation Entry to underground and Exit from the same shall be clearly defined and marked
at site.
 Vertical access shall be provided using steel ladder and/or stair tower for safe access to
excavated level.

Page 3 of 13
Method Statement for Excavation WORK

6.2. Utility Diversion

Diversion of utilities such as Water Mains, Electric, Telecom, Sewer and Storm Water & Diversion
of chartered utilities lying within and running parallel to the Diaphragm walls shall be carried out
prior to the commencement of the excavation works as far possible.

6.3. Monitoring and Instrumentation

In order to monitor ground water level, settlement of building/structures & ground surface,
deflection /movement of D-wall shall be done as per approved Instrumentation and monitoring
plan.

6.4. Excavation

For bottom-up construction

Excavation works for Bottom up construction shall be carried out by two different methods/
sequence:

Method-1:

 After the installation of soldier Pile as per approved method statement and drawings
excavation shall be carried out using excavator and dump trucks.
 Timber lagging shall be installed as the excavation progresses. The allowable depth of
excavation prior to installation of lagging shall depend on the actual ground conditions, Water
inflow or type of material, the depth below ground level and spacing between soldier pile. In
any case, this depth shall not exceed 1.50m and can be reduced to a depth of 2 or 3 timbers
while timber lagging is installed.
 The installation of timber lagging shall be as per drawings enclosed in appendix II & III.
 All the excavated material shall be disposed in dumping yard using tippers. Checking of the
all final formation levels shall be carried out with survey instruments. Levels shall be checked
before and after concreting has been done as per approved drawings.
 While the excavation carried on by mechanical means the required level of excavation for
base slab as per drawing shall be re- compacted to a dense smooth & level surface surface
both longitudinally and transversely.
 After completion of construction of a section of cut-and-cover/station box and backfilling,
sheet piles & soldier piles shall be pulled out, one at a time, using vidro- hammer. During the
extraction, voids will filed with sand

Method-2:

 The layer from existing ground level up to the final formation level shall be excavated by the
“conventional” method, i.e.by hydraulic excavators and/or shovels.

Page 4 of 13
Method Statement for Excavation WORK

 Excavation shall be started after construction of D-wall &installation of plunge column as per
approved MS. At the beginning of excavation works (up to below1st layer of strut), the pit
shall be accessed directly by the trucks over a ramp (this does not apply to the TBM
Launching pit). The trucks will be loaded directly by the excavators and crane. The
excavation shall be progressed by installing the strut&waler as per the Method Statement.
 At deeper excavation levels as well as for the TBM launching pit, the soil shall be hauled
vertically by 2 or 3 cranes carrying a bucket with a volume of appr. 5m³. For the TBM
Launching pit similar buckets of smaller size shall be used. Dozer shovel or loaders shall
haul the soil from the excavator to these buckets. While the crane will Lift one bucket, the
loader will fill the second bucket in the pit. The bucket shall be directly unloaded to the truck.
 In all cases material suitable for backfilling shall be separately dumped/stockpited and
unsuitable material shall be disposed off in dumping yard.
 Checking of the final formation levels shall be carried out with survey instruments. Levels
shall be checked before and after concreting as per approved drawings.
 While the excavation carried on by mechanical means the required level of excavation for
base slab as per drawing shall re-compacted to achieve a dense smooth &level surface both
longitudinally and transversely.

6.5. Examination of Exposed Diaphragm Walls

As the excavation proceeds, the exposed face of the Diaphragm walls shall be checked very
carefully for any defects e.g. honeycombing or bulging of concrete, seepage of water from
diaphragm wall and repaired using approved materials.

6.6. Temporary stockpile and disposal of excavated materials

Excavated material shall be collected temporarily at one place inside the site area and/or directly
loaded on to dump truck and transported to permanent/temporary disposal area. Dump trucks
should be loaded safely and without overloading. Soil shall be covered with Tarpaulin in loaded
trucks to avoid spillage/erosion during rain.
Each dump truck must display an authorization certificate confirming that it’s safe (tailgate, alarm
while reversing and road worthy). This certificate also allows entry to and from site and dumping
area.

Page 5 of 13
Method Statement for Excavation WORK

As the backfilling proposed to be carried out with the progressive casting of underground
structure, selected soil from excavated material shall be directly brought from the ongoing
excavation area for backfilling the structure. For surface water, any water during excavation or
rain water, sump should be provided at every 30m interval along with pumps of suitable capacity
for dewatering.

7. SAFETY
 Risk Assessment report attached as attachment 3 shall be used.
 Workers will wear helmets, Safety shoes/ Gum boots while working on site.
 Watchman will be available at each work site both during working and non-working hours.
 All excess excavated material, concrete, etc. will be cleared regularly.
 During excavation, watering platform around the panel shall be maintained clear of slurry,
concrete, water enchanted material etc. so that safe access is available.

8. QUALITY
 Inspection Test Plan attached as appendix 4 shall be used.

Page 6 of 13
Method Statement for Excavation WORK

9. EQUIPMENTS
List of Equipment attached as appendix 6 shall be used.

10. ATTACHMENTS

ATTACHMENT 1 LIST OF REFERENCES

ATTACHMENT 2 DRAWINGS & SKETCHES

ATTACHMENT 3 RISK ASSESSMENT & CHECKLISTS

ATTACHMENT 4 ITP, CHECKLISTS & FORMS

ATTACHMENT 5 CHECKLISTS / PERMITS

ATTACHMENT 6 EQUIPMENT LIST

Page 7 of 13
Method Statement for Excavation WORK

ATTACHMENT 1

LIST OF REFERENCES

6.1 Applicable specifications

Contract document Volume 5,Section 2.1

6.2 Applicable Project Procedures

None

6.3 Applicable Project MSs

 Method Statement for Diaphragm wall

 Method Statement for Roof Slab
 Method Statement for concourse slab
 Method Statement for base slab
 Method Statement for soldier pile
 Method Statement for cut & Cover base slab.

Page 8 of 13
Method Statement for Excavation WORK

ATTACHMENT 2

DRAWINGS / SKETCHES

Applicable Drawings

Attachment 2-1: Typical details for underground excavation

Page 9 of 13
Method Statement for Excavation WORK

ATTACHMENT 3

RISK ASSESSMENT

 JKIL- Risk Assessment

Page 10 of 13
Method Statement for Excavation WORK

ATTACHMENT 4

ITPs & CHECKLISTS

 JKIL- ITP for Excavation

Page 11 of 13
Method Statement for Excavation WORK

ATTACHMENT 5

CHECKLISTS / PERMITS

None

Page 12 of 13
Method Statement for Excavation work Doc No : JKIL-CRTG/CC24/MS/C/092(0)

ATTACHMENT 6

EQUIPMENT LIST

 Crawler crane 02 No.

 Auto Level/ Total Station As per requirement
 Welding machine 02 No.
 Hydraulic breaker 01No
 Dewatering pump 02 Nos
 Excavator 02Nos
 Dumper 05Nos
 Long boom excavator 01No.
 125 kvA DG sets 01 No.

Page 13 of 13