TRAINING UNDER DELHI METRO RAIL CORPORATION(DMRC),

JAIPUR

AREA OF TRAINING

• CONSTRUCTION OF DIAPHRAGM WALL

FOR UNDERGROUND METRO

STATION

• PILE FOUNDATION

GENERAL ABOUT THE PROJECT FOR UNDERGROUND METRO STATION

SCOPE- Construction of guide wall, trench excavation under bentonite, placing of reinforcement cage and concreting of diaphragm wall.

OWNER- DMRC

CONTRACTOR- ITD Cementation India Ltd.

TOTAL COST- 102Cr(approx)

LIST OF MAJOR PLANTS AND EQUIPMENTSS NO.

Plant/Equipment Type Number

1. 75t Capacity Crawler Excavation Crane/(Service)

2

2. Hydraulic and/or Rope Grabs 1

3. Bentonite Facility and Equipment 1(set)

4.

Stopend System As required

Continue …S NO. Plant/

Equipment Type

Number

5. Stopend Chisel As required

6. Tremie Pipe System(250mmdia) inc Hopper

2

7. Welding Sets 4

METHODOLOGY FOR THE CONSTRUCTION OF DIAPHRAGM WALL

The following steps were observed in the construction:1. Guide Wall

2. Bentonite Mixing

3. Excavation

CONTINUE …

4. Installation Of Stopened And Waterstopened

5. Reinforcement & Concreting

GUIDE WALLIt is temporary structure constructed priorto excavation of diaphragm wall.Purpose of guide wall:To ensure the stability and prevent the

collapsing of the soil strata.To provide temporary support for the

reinforcement cage.To provide the supports to Stopend.

STRUCTURAL DETAILS OF GUIDE WALL

Grade of concrete- M15

Thickness of Guide wall- 150mm

Depth of Guide wall- 1500mm

Continue…Clear cover- 25mm

Dia of steel used- 10mm & 8 mm at a distance of 250mm center to center.

Clear distance between inner faces of guide wall- diaphragm wall+50mm

Guide wall

BENTONITE MIXING

Mixing unit was erected on impermeable base to check spillage.

Kept in storage tank for 24hrs to hydrate.Continuously agitated using vertical pump.Daily bentonite test that were conducted- 1. ph- 9.3(9to11.5 as IS code9556-1980)

2. Density- 1.08(1.06to1.12 as Is code 9556-1980)

Bentonite

3. Sand Content-fresh(2%) & contaminated

(3%){7% as per Is code 9556-1980}

4. Viscosity- 45sec(32-90 sec as per Is code-9556-1980)

DIAPHRGAM WALL EXCAVATION

Wall is located between Guide wall.The trench was excavated using Hydraulic

Drilling Rig .Stopened with water stopened was then

lowered into the trench.Excavation was done in three panel(primary,

secondary & closing).Excavation was done with bentonite filled to

top level.

Diaphrgam wall

REINFORCEMENT & CONCRETING

Grade of steel- Fe500

Grade of concrete- M35

Dia of steels used- 35mm & 25mm

Continue …Minimum clear cover- 75mm

Shape of cover blocks- Circular

Horizontal distance of cover blocks- 1500mm

Concreting of Diaphrgam wall

• Vertical distance of cover blocks-2000mm

• Dia of tremie pipe- 250mm

• Length to which pipe was dipped inside the concrete- 2m

• Concreting was done to 1m above the cut off level.

Slump Test The test is an empirical test that measures

the workability of fresh concrete. More specifically, it measures consistency between batches. The test is popular due to the simplicity of apparatus used and simple procedure. The slump test is used to ensure uniformity for different batches of similar concrete under field conditions.

Types of slump

Continue…Collapse Shear True

In a collapse slump the concrete collapses completely. [2]

In a shear slump the top portion of the concrete shears off and slips sideways.[2]

In a true slump the concrete simply subsides, keeping more or less to shape.[2]

Slump Test

Test