Finite element analysis of lining of tunnel

Finite element analysis of lining of tunnel Gourab Mandal & A. K. Singh National Institute of Technology, Jamshedpur, Jharkhand, India ABSTRACT Tunnel play a vital role in our way of life as it eases the method of the transportation. Lining is the necessary

permanent ground support system to the periphery of a tunnel or shaft excavation, and/or the material installed in

the position with an inner surface suitable for the specific end use of the underground excavation. Lining of tunnel

is technically an important component and generally constitutes 30 % to 40 % of the total cost of the tunnel.

Therefore, lining operation requires considerable study and careful planning. Due to complexity of various

problems in engineering field, Finite Element Analysis [FEA] is widely used. It divides the domain of the problem

into several sub-domains thus it is easier to solve the complex problem. In this paper, cut and cover canal tunnel

lining subjected to gravity load, horizontal and overburden pressure using FEA based software “GTS-NX” and the

thickness of the tunnel has been designed and the result is compared with USBR method. Thickness of tunnel

lining for lower overburden loading over crest in both the analysis is same but for higher overburden loading (8 m

and 11 m), thickness is slightly less in GTS-NX than USBR monogram method.

1 INTRODUCTION

Tunnel play a vital role in our day to day life as it

made easy the transportation. In developing country

like India, due to rapid urbanization, development,

industrialization & civilization, there is scarcity of land,

and hence tunnel is important. In case of metro

tunnel, it can be constructed underground. Further, for

civic needs in developing country, tunnel can be used

for shelters, recreations, defence, water conductor

system, commercial activities, etc. The first tunnel

was constructed by Sir Marc Isambard Brunel and his

son Isambard Kingdom Brunel under the Thames

River (London) between 1825 and 1843.Bull (1944)

divided the tunnel ring into 16 equal divisions with

external loads combined to give 16-point loads, one

acting upon each division. Terzaghi (1948) formulated

the first rational method of evaluating rock loads

appropriate to design of steel arches. Philips and

Allen (1968) analysed different shapes of tunnel for

three values of crown thickness, t, expressed in terms

of the internal crown radius. A conduit of unit length

was considered in the analysis. Bending moment,

thrust and shear coefficient were determined at

various locations, and are expressed in terms of unit

intensity of loading and unit internal crown radius. IS:

4880-Part IV (1971) has set of basic equations for

calculating radial stress, tensile stress in concrete

lining and surrounding rock mass for the design of

tunnel lining for internal water pressure and bending

moment, normal trust, radial trust, radial shear,

horizontal shear and vertical deflection in the concrete

lining and surrounding rock mass for the design of

tunnel lining for external load. Kumar & Singh (1990)

described that the concrete lining of pressure tunnels

needs to be reinforced on several situations. The

amount of reinforcement in the lining and its spacing

must be selected to ensure a reasonable crack width

and distribution of crack. Toma (2011) provided

programming to choose suitable tunnel lining methods

from different lining methods available such as

precast concrete segments, cast steel segments, cast

in place concrete, pipe jacking and shotcrete lining.

Zakir et al. (2015) made an analysis on modelling of

TBM segmental lining at accidental cases. An

appropriate model for simulating segmental lining

components was made using Midas GTS-NX.

1.1 Lining of Tunnel

Lining is the permanent support system to the

periphery of the tunnel, play the main role to protect

tunnel from collapse and provide safety. It usually

consists of precast concrete segments which form

rings. Cast iron linings were traditionally used in

tunnels, while steel liners were sometimes used

elsewhere. Lining may be of timber, steel, masonry,

precast and cast in-situ concrete, fibre-reinforced

concrete.

1.2 Methods of Tunnel Lining

There are various methods of construction of tunnel

are:

(i) Cut and Cover Method of Tunnel Construction

(ii) Tunnel Boring Machine (TBM) Method

(iii) Shaft Tunnelling Method

(iv) Drilling and Blasting Method

(v) Underwater Tunnelling Method

1.3 Factors Affecting Lining

There are various factors on which tunnel lining

depends:

(i) Tunnel function

(ii)Tunnel cross sectional profile

(iii) Groundwater conditions

(iv) Ground condition

1.4 Importance of Finite Element Method

Finite element analysis (FEA) has developed

simultaneously with the increasing use of high speed

computers and with growing emphasis on numerical

methods for engineering analysis. Although, the

method was developed originally for structure

analysis, the general nature of the theory on which it

was based has also made possible its successful

application for solutions of problems in other fields of

engineering. The general principle is “going from part

to whole” as it breaks up the continuum into discrete

number of smaller elements. Finite element can be

applied in two ways i.e. first is analytical solution and

second using software. Due to innovation and

development of different kind of software, it is easier

to apply finite element method in the field of

engineering application. Nevertheless, the method

can also be applied to non-linear elastic problems.

1.5 Importance of the Study

In the hilly region like Jharkhand, surface level is

undulated, and it is very difficult to construct canal

without elevated section or underground section.

Level should be maintained in canal to flow water and

if elevated ground surfaces or hill is encountered in

the way of canal, then it is highly essential to

construct underground tunnel. There is scarcity of

water in Jharkhand and hence dam and canal are the

only solution to supply water. The primary objective of

the study is to analyse the forces and reactions acting

on the tunnel lining, study the effect of arching of soil

on the tunnel lining. The design of the tunnel lining

section is the other objective of this study. In this work

“GTS-NX” software has been used for analysis of

tunnel lining.

2 THEORETICAL ANALYSIS

2.1 Arching of Soil

Arching effect is one of the most universal

phenomena encountered in soils both in the field and

in the laboratory. Arching can be best described as a

transfer of forces between a yielding mass of geo-

material and adjoining stationary members. A

redistribution of stresses in the soil body takes place.

The shearing resistance tends to keep the yielding

mass in its original position resulting in a change of

the pressure on both of the yielding part's support and

the adjoining part of soil. If the yielding part moves

downward, the shear resistance will act upward and

reduce the stress at the base of the yielding mass. On

the contrary, if the yielding part moves upward, the

shear resistance will act downward to impede its

movement and cause increase of stress at the

support of the yielding part. Depending upon relative

stiffnesses in the ground mass, arching can either be

active or passive. Active arching occurs when the

structure is more compressible than the surrounding

soil. In passive arching, the soil is more compressible

than the structure.

2.2 Theory of Arching in Soil

The stress condition within the backfill show that the

arching is generally governed by the void, trenches,

filling areas, wall roughness i.e. interface friction

angle(δ), friction angle of the backfill material (ϕ), unit

weight of backfill (γ). Two essential prerequisite for

arching phenomenon to be developed in soil are

(i) Inducement of relative movement within the soil

mass

(ii) Availability of shear strength

2.2.1 Terzaghi’s Theory of Arching

The theory is based on the assumption:

(i) Arching is fully developed.

(ii) Surface of sliding are vertical and shear strength is

fully mobilized on these surfaces.

The real surfaces of sliding, as observed by Terzaghi

in 1936, are curved and at the soil surface their

spacing is greater than the width of the yielding strip.

The yielding strip ‘ab’ at the solid base is presented in

Fig. 1, and the real sliding surfaces are curve ac and

curve ‘db’ in the same figure. The sliding surfaces are

assumed to be vertical. The vertical sections ‘ae’ and

‘bf’ through the outer edges of the yielding strip in Fig.

1 represent surfaces of sliding. The pressure on the

yielding strip is thus equal to the difference between

the weight of the sand located above the strip ‘ab’ and

the shear resistance along the vertical sections. The

free body diagram for a slice of soil in the yielding

zone above strip ‘ab’ is presented in Fig. 2. In addition

to the vertical sliding surface assumption, Terzaghi

also assumed that the normal stress is uniform across

horizontal sections and the coefficient of lateral stress

(K) is a constant. Cohesion (c) was assumed to exist

along the sliding surfaces.

Figure 1. Yielding in soil caused by downward

movement of a long narrow section (ab) at the base;

curve ‘ac’ & ‘bd’: actual sliding surfaces, line ‘ae’ &

‘bf’: assumed sliding surfaces

Figure 2. Free body diagram for a slice of soil in the

yielding zone

The vertical equilibrium for the free body in Fig. 2 is:

2Bγdz = 2B (σv+ dσv) - 2Bσv+ 2cdz + 2σhdztanϕ [1]

where,

2B = width of the yielding strip (ab), z = depth, γ = unit

weight of soil, σv = vertical stress, σh = horizontal

stress = Kσv, K= the coefficient of lateral stress, c =

cohesion, ϕ= friction angle.

The boundary conditions are σv= q (surcharge) at z

=0. Solving Equation [1], leads to

σv = B (γ−

c

B)

K.tanϕ(1 − exp(− K (

z

B) tanϕ) + q

exp(− K (z

B) tanϕ) [2]

where, q = surcharge at the soil surface.

Terzaghi applied the aforementioned theory to tunnel

design (Terzaghi, 1943). The state of stresses in the

soil above the top of a tunnel is similar to the state of

stress in the soil above a yielding strip. Terzaghi

assumed the soil adjacent to the tunnel yields laterally

toward the tunnel during construction. This creates an

active earth pressure condition with the boundaries of

the yielding zone inclined at about (45°+ϕ/2).

At the level of the tunnel roof, the width of the yielding

strip (2B1) for a rectangular tunnel is

2B1= 2[Bo+ H tan (45 -ϕ

2)] [3]

If the tunnel roof is located at a depth Din the ground,

the vertical stress on the roof is

σv=B1 (γ−

c

B)

K.tanϕ(1 − exp(− K (

D

B1) tanϕ)) [4]

If a tunnel is located at a great depth below the

surface, the arching effect cannot extend beyond a

certain elevation D1above the tunnel roof (like z2in the

last section, Figure 1). Also, the soil located above

this elevation has a depth D2(z1 in Fig. 1). The vertical

stress on the roof is then expressed as:

σv = B1 (γ−

c

B)

K.tanϕ(1 − exp(− K (

D1

B1) tanϕ)) +

𝛾D2 exp(− K (D1

B1) tanϕ) [5]

When D, is very large, the vertical stress σv will reach

a limit value

σv = B1 (γ−

c

B)

K.tanϕ [6]

If the tunnel is constructed in sand, then cohesion (c)

is equal to 0. However, for safety reasons, c = 0 is

assumed and equation [6] can be simplified to:

σv = B1γ

K.tanϕ [7]

2.2.2 USBR Monogram Method

This monograph presents the result of stress analysis

by means of Beggs Deformer Apparatus, of nine

shaped single barrel conduits. A partial analytical

check was made using the least work method

redundant reaction for all shapes for a uniform vertical

load and a uniform horizontal load. Reaction

coefficient for bending moment, shear and thrust at

selected location due to centroidal axis of conduits

have been determined for 15 different loading

conditions. Bending moment, thrust, shear

coefficients were determined at various location are

shown are expressed in terms of unit intensity of

loading and unit internal crest radius. Multiplying the

reaction coefficient by proper load factor gives the

actual values of bending moment, thrust and shear at

the centroid of the section under consideration. As the

foundation modulus increases, the foundation load

approaches a concentration at the outside corner of

the conduit and as it decreases the load approaches

uniform distribution. So, in case of rock foundation

triangular foundation reaction occurs and in case of

pure soil uniform foundation reaction occurs.

Figure 3. ‘D’ shaped tunnel lining with various

segment

3 RESULT AND DISCUSSION

3.1 General

The present study of analysis and design of lining of

canal tunnel is a live project being constructed by

Department of Irrigation, under Swarnrekha multi-

purpose project at Sundernagar for canal starting

from Ganjia Barrage (on Kharkai River) towards

Jadugora, Jamshedpur, Jharkhand. In the present

work, analysis of forces and moments acting on ‘D’

shaped tunnel lining has been analysed properly. The

most critical loading condition is considered due to

overburden, backfill, self-weight of structure and

empty condition of tunnel. If water is flowing inside

the tunnel, then it will counter balance the horizontal

thrust acting on the tunnel lining. In rainy season or in

case of flood, the backfill material gets fully saturated

and this saturated unit weight of backfill material is the

most critical condition of tunnel lining.

Vertical stress on the crest of the tunnel

lining due to overburden pressure above the crest is

considered partially due to “Arching Effect” as per IS

code: 7563 (1986). Analysis is done with “GTS-NX”

software, based on the finite element method. It helps

engineers to perform step-by-step analysis of

excavation, banking, structure placement, loading and

other parameters that directly affect design and

construction. After substituting all loading conditions

and boundary conditions moment, thrust and shear

force have been obtained. These are also calculated

using USBR monogram method. The values obtained

from USBR monogram (Verma, 2017) compared with

the value that are obtained from the software.

To analyse the tunnel problem with software,

total 62 nodes has been considered. So, half of the

tunnel is divided into 32 nodes and then moment,

thrust and shear force at each node has been

calculated. After getting the combined moment, thrust

and shear force, dimension of the tunnel lining section

has been designed for the critical nodes keeping in

view the safety of tunnel lining.

3.2 Result of Moment, Thrust and Shear due to

various loads

There are five types of loads and reaction acting on

the tunnel lining namely self-weight of tunnel, uniform

horizontal load (both side), triangular horizontal

loading (both side), uniform vertical load with uniform

foundation reaction; and uniform vertical load with

triangular foundation reaction has been considered.

Arching effect has been considered as per IS code

and vertical stresses have been computed. In USBR

monogram the tunnel is divided into 14 segments and

in software 32 node. Values reported at each

segment are compared with present values obtained

at corresponding nodes.

3.2.1 Illustrative Example

An illustrative example is considered to compute

moment, thrust and shear of ‘D’ shaped tunnel and

details as follows:

Width of tunnel lining = 5.0 m, Height of crest

= 5.0 m, Radius of arch = 2.5 m, Height of overburden

over crest = 8.0 m, Width of trench at crest level =

7.0m, Saturated unit weight of backfill = 22 kN/m3.

Solution: These nodes and elements are

shown in Fig. 4 and Fig. 5 respectively. Half left side

of the tunnel is represented in Fig. 6.

Figure 4. Nodes of the tunnel

Figure 5. Elements of the tunnel

Figure 6. Half left side nodes of the tunnel

The tunnel is analysed for different loading and the

variation of moment, thrust and shear are calculated.

The distribution of moment thrust and shear force due

to triangular horizontal loading have been represented

in Fig. 7 to Fig. 9. The values are tabulated in Table 1.

Figure 7. Moment distribution due to triangular

horizontal load of tunnel

Figure 8. Axial thrust distribution due to triangular

horizontal load of tunnel

Figure 9. Shear force distribution due to triangular

horizontal load of tunnel

Table 1. Distribution of thrust, shear and moment due

to horizontal triangular loading

NODES MOMENT

(kNm)

THRUST

(kN)

SHEAR

(kN)

1 23.4412 0 -0.5546

2 -6.459 0 36.4277

3 -1.288 0 31.0224

4 1.5968 0 26.1562

5 3.4198 0 20.8155

6 5.5675 0 15.4133

7 9.2147 0 11.2375

8 13.0554 0 7.2256

9 15.7454 0 5.3215

10 19.6475 0 3.351

11 23.4158 0 1.5944

12 27.1205 0 0.5468

13 17.2445 0 -1.2378

14 14.625 1.3226 -4.1245

15 -8.1154 36.3125 0

16 8.2104 4.1725 -7.7263

17 3.1049 7.1461 -11.8026

18 -8.1154 36.3125 0

19 -2.1947 13.2347 -15.4157

20 -8.1154 36.3125 0

21 -8.1154 36.3125 0

22 -7.4546 19.1594 -18.3141

23 -8.1154 36.3125 0

24 -12.015 22.0254 -14.5476

25 -8.1154 36.3125 0

26 -17.2241 25.5657 -7.4519

27 -8.1154 36.3125 0

28 -8.1154 36.3125 0

29 -22.1594 27.3885 -11.0144

30 -8.1154 36.3125 0

31 -8.1154 36.3125 0

32 -25.4319 29.5342 -4.1375

Similarly, the values of moment, thrust and shear are

calculated for the other cases. Results show that out

of all the loading conditions, the most influencing load

is uniform vertical load, Reaction offered by rock is

less influencing than soil. Maximum bending moment

occurs at the 32nd node i.e. middle of the base slab of

the tunnel lining whereas thrust occurs at 3rd node

which is located at the horizontal junction of vertical

wall and base slab and maximum shear occurs at 18th

node i.e. at the vertical junction of vertical wall and

base slab. After analysing the different load acting on

the tunnel, the values are compared with the values

obtained using USBR monogram (Verma, 2017). In

software analysis, total 32 nodes are considered in

analysis whereas in USBR monogram half of the

tunnel is divided into 14 segments. So, in “GTS-NX”

analysis in each segment, several points are lied.

Comparison is made by taking the suitable node at

each segment. Comparison of the values of moment,

thrust and shear due to horizontal uniform loading is

shown in Table 2.

Table 2. Comparison of the values obtained for Horizontal Uniform Loading between USBR and GTS-NX

Node MOMENT (kNm) THRUST (kN) SHEAR (kN)

USBR GTS-NX USBR GTS-NX USBR GTS-NX

1 -75.534 -73.125 83.4626 68.0254 0 0

2 -65.95 -68.327 76.0688 65.1185 -28.389 -21.386

3 -39.707 -52.318 65.8957 59.287 -49.566 -45.239

4 -3.423 -8.9155 48.1462 43.3125 -58.146 -59.122

5 33.7736 21.0578 30.1228 22.6325 -52.122 -47.823

6 62.755 65.1295 0 0 -33.318 -36.45

7 76.447 78.0975 0 0 -6.9374 -3.6441

8 69.601 64.3112 0 0 23.4593 23.047

9 37.1966 34.4235 0 0 53.9472 57.1241

10 -20.31 -21.788 99.5878 102.927 84.3439 85.3275

11 -37.881 -39.664 99.5878 102.927 0 0

12 -37.881 -39.664 99.5878 102.927 0 0

13 -37.881 -39.664 99.5878 102.927 0 0

14 -37.881 -39.664 99.5878 102.927 0 0

After comparison, it is seen that the value obtained

from USBR method is well agreement with the

value obtained from GTS-NX. The maximum values

for moment, thrust and shear is occurring at the

similar segments. In USBR monogram analysis

(Verma, 2017) the maximum bending moment

occurs at 14th segment i.e. middle of the base slab

of the tunnel lining whereas maximum thrust occurs

at the 10th segment i.e. at the horizontal junction of

the vertical wall and base slab and maximum shear

occurs at 11th segment i.e. at the vertical junction of

vertical wall and base slab. The critical values

obtained from GTS-NX software at the same points

as in the USBR method.

Since the uniform vertical load is most

influencing load so distribution of moment, thrust

and shear due to different height above crest 4 m, 8

m & 11 m are analysed, and variation is shown in

Fig. 10 to Fig. 12.

Figure 10. Segment wise variation of moment for

different overburden above crest

Figure 11. Segment wise variation of thrust for

different overburden above crest

Figure 12. Segment wise variation of shear force for

different overburden above crest

0

5

10

15

20

-500 0 500 1000

Segm

ent

Moment (kNm)

4 m 8 m 11 m

02468

1012141618

-200 0 200 400 600 800

Segm

ent

Thrust (kN)

4 m 8 m 11 m

0

5

10

15

20

-1000 -500 0 500

Segm

ent

Shear (kN)

4 m 8 m 11 m

3.3 Combined Moment, Thrust and Shear force

For all four loading condition and two foundation

reactions (uniform in case of soil and triangular

foundation reaction in case of rock), combined

bending moment, thrust and shear have been

analysed. The loading diagram and their variation in

moment, thrust and shear is shown in Fig. 13 to Fig.

16.

Figure 13. Combined load acting on tunnel

Figure 14. Moment distribution due to combined

Loading on tunnel

Figure 15. Thrust distribution due to combined

Loading on tunnel

Figure 16. Shear force distribution due to combined

loading on tunnel

The foundation of tunnel at Sundarnagar site,

proportion of soil and rock is 40% and 60%

respectively. So, for design purpose, 40%

weightage has been given to soil and 60%

weightage has been given to rock and combined

weightage has been presented in Table 3. It is

totally engineering judgement of

researcher/designer.

Table 3. Distribution of combined moment, thrust

and shear due to various loads and combined

foundation reaction

NODES MOMENT (kNm)

THRUST (kN)

SHEAR (kN)

1 -62.2231 606.07384 -81.03886 2 7.3901 606.07384 112.25914 3 -4.52006 606.07384 88.2673 4 2.9757 606.07384 69.4138

5 28.79004 606.07384 30.81086 6 54.12722 606.07384 14.0247 7 60.2257 606.07384 3.089 8 70.85174 606.07384 -5.73498 9 45.9371 606.07384 -16.47206 10 24.10746 606.07384 -23.81198 11 5.3096 606.07384 -28.45608 12 -33.71078 606.07384 -56.2154 13 -181.4483 536.70874 -57.85242 14 -203.2203 504.44444 -19.6749 15 114.68 144.67152 -495.2559 16 -167.86514 457.7847 51.9565

17 -108.5459 427.50584 74.34016 18 46.00606 130.9452 -62.44494 19 -54.20686 389.91316 134.53966 20 101.82582 130.9452 -24.62998 21 118.55048 130.9452 -9.8395 22 2.8752 352.7627 106.1835 23 151.73252 130.9452 -5.63516 24 71.33366 292.5383 81.17452 25 182.2574 130.9452 -2.0156 26 171.5351 256.1523 53.69872 27 223.75252 130.9452 0 28 278.38822 130.9452 0

29 211.08818 227.27622 27.9884 30 310.0687 130.9452 0 31 351.46484 130.9452 0 32 238.74042 201.35128 -7.9847

The value of moment, thrust and shear obtained for

the case of combined all four loading by considering

proportion of soil and rock is 40% and 60%

respectively from “GTS-NX” software is compared

with values obtained from “USBR” monogram

method. The value at important segment is

compared in Table 4.

Table 4. Comparison of moment, thrust and shear between USBR and GTS-NX software

Segment

Moment (kNm) Thrust (kN) Shear (kN)

USBR GTS-NX USBR GTS-NX USBR GTS-NX

1 214.5431 238.7404 170.3616 201.3512 -6.1589 -7.9487

4 -101.2425 -108.545 366.4601 389.3731 143.8951 134.5396

7 -69.1793 -62.2231 574.665 606.0738 -35.0147 -56.2154

11 136.8798 114.68 600.3691 606.0738 -466.9874 -495.2559

14 328.1205 351.4648 112.4109 130.9452 0 0

4 CONCLUSIONS

On the basis of the results and religious discussion

made, important conclusions are drawn as follows:

Thickness of tunnel lining for lower

overburden loading over crest in both the analysis is

same but for higher overburden loading (8 m and 11

m) thickness is 450 mm and 550 mm in GTS-NX

whereas 500 mm and 600 mm in USBR monogram

method. Thickness of tunnel lining for different

parameters of soil obtained in GTS-NX is less than

USBR monogram method.

It is obvious that with increase of radius of

tunnel the thickness of lining increases, but the

thickness of tunnel for different radius obtained in

GTS-NX is less in comparison to USBR.

The lining of tunnel has been analysed in

USBR monogram method, values obtained for

bending moment, thrust and shear using obtained

from “GTS-NX” is compared for all the cases. It has

been seen that the values obtained in both cases

are nearby equal. Hence, it can be concluded that

the analysis using “GTS-NX” software results in

more economical. So, one can prefer to analyse

and design the tunnel using “GTS-NX” software.

Arching of soil plays very important role in

computing the loads and reactions acting on the

tunnel lining. Arching of soil reduces the vertical and

horizontal pressure due to overburden above the

crest.

The most critical loading condition is due

to overburden, backfill, self-weight of structure and

empty condition of tunnel. Buoyant force, uplift

pressure and seepage force do not play vital role in

most critical loading condition.

5 REFERENCES

IS: 4880(PART IV)-1971, Structural design of

concrete lining in rock, BIS New Delhi.

Jaafar, Md. 2017. Numerical modelling for circular

tunnel under static and dynamic Load, VSB-

Technical University of Ostrava.

Mouratidis, A. 2008 The ‘Cut and Cover’ and ‘Cover

and Cut’ technique in highway engineering,

Electronic Journal Geotechnical Engineering, Vol.

13.

Palassi, M. and Mohebbi, M. 2015. Design of lining

of tunnels excavated in soft soil and rock, University

of Tehran, Iran.

Philips, H. B. and Allen, I. E. 1968. Beggs

deformeter stress analysis of single barrel conduits,

United States Bureau of Reclamation, United

States.

Singh, B. and Kumar, P. 1990, Design of reinforced

concrete lining in pressure tunnel, Tunnelling and

Space Technology, 5: 591-601.

Terzaghi, K. 1943. Theoretical soil mechanics, John

Wiley and Sons, New York. Verma, P.

2017.Analysis and design of lining of canal tunnel,

M. Tech. Dissertation submitted in Deptt. Of Civil

Engg., N.I.T. Jamshedpur