SCOPE AND OBJECTIVE

This thesis presents the results of a case study on the penetration diameter of cement based

permeation grout in soil with respect to various grouting parameter. Different imperial

relationship between soil properties and grouting characteristics are also presented.

An experimental study on the penetration diameter of cement grout mixes with water/cement

ratio (W/C, by weight) of 1.0, & 1.5 is observed under constant grout discharge at various depth.

Again the observation is taken with respect to constant injection pressure at various depth. Field

samples are collected and compression strength are performed and compared with laboratory test

samples.

The present research provides with the following useful information for enhancing the design

and application of cement based permeation grouting using existing flow models in design

practice.

1. To provide an empirical relationship between injection diameter and injection pressure

with respect to water cement ratio and nature of soil.

2. To provide an empirical relationship between injection diameter and injection rate with

respect to different water cement ratio and nature of soil.

3. To provide an empirical relationship between injection pressure and injection rate with

respect to different Field SPT.

4. Comparative study of strength of grouted soil samples from field to the strength of

grouted soil in laboratory.

.

THEORETICAL BACKGROUND OF GROUTING

Grout permeation through soil is related to the grouts permeability, measured in term of the

coefficient of permeability k according to Darcys law. There are two models regarding grout

flow through porous media.

1. Spherical flow model

2. Cylindrical flow model

Spherical Flow Model for Porous Media for Newtonian Fluid

Net pressure (Pe) in excess of local hydrostatic pressure necessary to maintain the flow from a

spherical cavity of radius of Ro is a function of the grouting rate, the soil permeability and the

viscosity of grout as expressed in the following relationship.

Q = grouting rate, m3/s

= unit weight of grout, kN/m

Kg = permeability of soil to grout, m/s

k = permeability of soil to water, m/s

= viscosity of Newtonian grout, Pas

w = viscosity of water, Pas

R = distance from grouting point

R= radius of injection hole

The time required to travel a distance R from a spherical cavity with radius Ro can be computed

by :

( )

Radial Flow model for porous media through Cylindrical Cavity for Newtonian Fluid

Net pressure (Pe) in excess of local hydrostatic pressure necessary to maintain the flow through a

cylindrical cavity is a function of the grouting rate, the soil permeability and the viscosity of

grout as expressed in the following relationship.

(

)

The time required to travel a distance R from a spherical cavity with radius Ro can be computed

by :

( )

n = porosity of the soil

m = thickness of the layer to be grouted, m

TEST PROCEDURE

COSTANT INJECTION RATE

Four permeation tests are proposed at field level to verify the penetration radius of cement based

grout under constant injection rate with water cement ratio 1.0 and 1.5 respectively.

Total permeation depth is considered to be 6m. We have assumed the distance (m) between the

peckers is 2.0m. Radius of the hole is 0.1m. Injection rate is kept constant at a particular depth

for a specified period of time and injection pressure is measured.

Following Properties of grout is assumed to determine theoretical injection diameter

Discharge (m3/s), Q= 0.0015, 0.0030, 0.0045, 0.0060

Unit Weight of Grout (kN/m3), =15 (For W/C = 1.0), =22.5 (For W/C = 1.5)

Thickness of Layer (m), m= 1.5

Permeability of Soil -Grout (m/s), Kg=0.00001(For W/C = 1.0), Kg=0.0000067(For W/C = 1.5),

Radius of Hole (m), Ro=0.1

Porosity, n=0.3

Time(s), t=300&600

W/C=1.0, Injection Time = 300s

Depth (m) Rate ( m3/s) Time (S) Net Pressure (KPa) Diameter ( m) W/C

1.5 0.0015 300 240.59 0.5731 1

3 0.003 300 479.79 0.804 1

4.5 0.0045 300 718.84 0.983 1

6 0.006 300 957.84 1.133 1

W/C=1.5, Injection Time = 300s

Depth (m) Rate ( m3/s) Time (S) Net Pressure (KPa) Diameter ( m) W/C

1.5 0.0015 300 536.49 0.573 1.5

3 0.003 300 1071.57 0.804 1.5

4.5 0.0045 300 1606 0.983 1.5

6 0.006 300 2141 1.133 1.5

W/C=1.0, Injection Time = 600s

Depth (m) Rate ( m3/s) Time (S) Net Pressure (Kpa) Diameter ( m) W/C

1.5 0.0015 600 240.94 0.804 1

3 0.003 600 480.13 1.133 1

4.5 0.0045 600 719.18 1.38 1

6 0.006 600 958.19 1.6 1

W/C=1.5, Injection Time = 600s

Depth (m) Rate ( m3/s) Time (S) Net Pressure (Kpa) Diameter ( m) W/C

1.5 0.0015 600 536.83 0.804 1.5

3 0.003 600 1071.92 1.133 1.5

4.5 0.0045 600 1606.86 1.386 1.5

6 0.006 600 2141.76 1.6 1.5

0.5731

0.804

0.983

1.133

0.804

1.133

1.38

1.6

0

0.2

0.4

0.6

0.8

1

1.2

1.4

1.6

1.8

0.4

0.6

0.8

1

1.2

1.4

1.6

0.001 0.002 0.003 0.004 0.005 0.006

DIA

MET

ER (

m)

DISCHARGE ( m3/s)

Theoritica Diameter (m) Vs Discharge (m3/s)

W/C = 1.0 & 1.5 Time=600s

W/C = 1.0 & 1.5 Time=300s

0.5731

0.804

0.983

1.133

0.804

1.133

1.38

1.6

0.804

1.133

1.386

1.6

0.573

0.804

0.983

1.133

0.35

0.55

0.75

0.95

1.15

1.35

1.55

0 250 500 750 1000 1250 1500 1750 2000

Dia

me

ter

( m

)

Injection Pressure (KPa)

Theoritical Diameter (m) Vs Pressure (KPa)

240.59

479.79

718.84

957.84

536.49

1071.57

1606

2141

0

500

1000

1500

2000

0.001 0.002 0.003 0.004 0.005 0.006

Inje

ctio

n P

ress

ure

(K

Pa)

Discharge ( m3/s)

Injection Pressure (KPa) Vs Discharge (m3/s)