Target GATE & ESE 2022 (Geotechnical Engineering-II)

Q.1 A and B are Skempton's pore pressure coefficients. For saturated normally consolidated soils

 (a)  A>1 and  B>1                        (b)  A>1 and B<1

 (c)  A<1  and B>1                        (d)  A< 1 and B=1

Q.2 Consider the following statements:

 1. Pore pressure parameter A is a constant for a soil.

 2. The shear strength of soil is a function of the effective stress in the soil and not of the total stress in the soil.

Which of the statements given above is/are correct

(a) 1 only                                  (b) 2 only

(c) Both 1 and 2                       (d) Neither 1 nor 2

Q.3 Consider the following statements:

1. Brittle behavior of soils can be obtained when soil is heavily over-consolidated clay.

2. For a saturated soil Skempton's B-parameter is nearly equal to unity.

3. In UCS test minor principal stress equal to zero.

Which of these statements is/are correct

(a) 1,2 and 3             (b) 2 and 3             (c) 1 only        (d) 3 only

Q.4 In an unconsolidated undrained triaxial test it is observed that an increase in cell pressure from 150 kPa to 250 kPa leads to a pore pressure increase of 80 kPa. It is further observed that an increase of 50 kPa in deviatoric stress results in an increase of 25 kPa in the pore pressure. The value of Skempton's pore pressure parameter B is:

(a) 0.5                                           (b) 0.625

(c) 0.80                                         (d)   1.0

Q.5 A clay soil sample is tested in a triaxial apparatus in consolidated drained conditions at a cell pressure of 100 kN/m^2. What will be the pore water pressure at a deviator stress of 40 kN/m^2?

 (a) 0                                          (b) 20 kN/m^2

 (c) 40 kN/m^2                          (d) 60 kN/m^2

                                  

Assignment (Irrigation Engineering)

 Assignment (Irrigation Engineering)

Assignment (Introduction to Fluid Mechanics)

 Assignment (IFM)

Assignment (Geotechnical Engineering-II)

 Assignment (GE-II)

Target GATE & ESE 2022 (Fluid Mechanics)

 Do You Know ?

👉As per Bernoulli's equation:

      Total head = P/Y + V^2/2g + z

      Piezometric head = P/Y + z

     Velocity head or kinetic head or dynamic head = v^2/2g

      Stagnation head = P/Y + V^2/2g  

👉Cavitation is the formation of vapour bubbles in a flowing liquid in the region where the pressure falls below vapour pressure and sudden collapsing of these vapour bubbles in a region of high pressure causes pitting.

👉 If time of closure (T) is less than equal to 2L/C  → closure is sudden or instantaneous

👉  If time of closure (T) is greater than  2L/C  → closure is gradual or slow.

👉 In case of sudden closure, when pipe is rigid 

                                     P = ρ CV       

      This formula is called Allievi Formula

👉Loss of head in both the cases, sudden expansion and sudden contraction happens due to formation of eddies, but the intensity is more in case of sudden expansion. Loss will be more in case of sudden expansion.

    Another reason for more loss in case of sudden expansion is the deceleration of flow due to area expansion.

👉Surge tanks are used to absorb the increase in pressure due to water hammer phenomenon.

👉 Condition to satisfy Hardy Cross Method (Trial & Error Solution)

     > The flow into any junction must equal the flow out of the junction (Continuity principle)

     > The Darcy-weisbach equation must be satisfied for each pipe (hf = rQ^n)

     > The algebric sum of head loss around any closed circuit will be zero when discharge distribution is correct.  

                

                      Note: If you really like this concept please follow talktorashid.blogspot.com

Target GATE & ESE 2022 (Irrigation Engineering)

 Solution of Class Test (Irrigation Engineering)

Target GATE & ESE 2022 (Introduction to Fluid Mechanics)

Solution (Introduction to Fluid Mechanics)

Target GATE & ESE 2022 ( Geotechnical Engineering Quiz Solution)

 Target GATE & ESE 2022 ( Geotechnical Engineering Quiz Solution)

Target GATE & ESE 2022 (Geotechnical Engineering)

 Q.1 Consider the following:

1. Closing the drainage valve.

2. Opening the drainage valve

3. Applying cell pressure

4. Shearing

What is the correct sequence of operation for conducting CU triaxial test?

(a) 1-2-3-4                   (b) 3-2-1-4

(c) 2-1-3-4                   (d) 2-3-1-4

Q.2 The unconfined compressive strength of pure clay soil is 100 kN/m^2. What is the value of cohesion of the soil in kN/m^2?

(a) 200       (b) 100       (c) 75        (d) 50

Q.3 Assertion(A): Total stress analysis is adopted for long term stability problems.

      Reason (R): Total stresses and effective stresses are numerically the same after excess pore water pressure is dissipated.

(a)             (b)             (c)              (d)

Q.4 The confining pressure and the deviator stress on a triaxial sample are, respectively 100 kN/m^2 and 300 kN/m^2. What is the normal stress acting the plane of maximum shear stress?

(a) 150 kN/m^2                (b) 200 kN/m^2

(c) 250 kN/m^2               (d) 400 kN/m^2

Q.5 What is the appropriate field test to determine the in-situ undrained shear strength of a soft clay?

(a) Static cone penetration test (SCPT)

(b) Standard penetration test (SPT)

(c) Plate load test

(d) Vane shear test

                                       Happy Learning

 

Target GATE & ESE 2022 (Geotechnical Engineering)

 Do You Know?

👉Bridge abutments are restrained by deck slab, so earth pressure acting on abutment is earth pressure at-rest.

👉For initial stability ⇒ Undrained test is considered. To be on more safer side saturated clay is taken as unconsolidated.

👉 Unconfined compression test is a special case of triaxial test in which minor principal stress (Cell pressure=0) is zero. Mohr-circle passes through origin.

👉 Consolidated means drainage is allowed in first stage (Cell pressure stage or confining stage) and drained means drainage is allowed in second stage (Deviator stage/shear stage). In CD test drainage is allowed (drainage valve is open) in both the stages hence pore water pressure is zero in both stages.

👉Point above Mohr's envelope indicates that shear stress is more than shear strength of soil which is an imaginary condition.

👉 For Initial Stability(Short term stability) →  UU test

      For Long term stability →CD test

👉Liquefaction is generally associated with sandy soil and not possible in normal clays due to cohesion between particles (shear strength not equal to zero) but highly sensitive clay may undergo liquefaction under vibration.

     

Target GATE & ESE 2022 (Fluid Mechanics)

 Q.1 If the velocity of flow as well as the diameter of the flowing pipe are respectively doubled through a pipe system in use since long, the head loss will thereafter be

(a) Halved    (b) Doubled          (c) Increased 4 times       (d) No change

Q.2 Two tanks are connected in parallel by two pipes A and B of identical friction factors and lengths. If the size of pipe A is double that of pipe B, then their discharges will be in the ratio of

(a) 2           (b) 4     (c) 5.66           (d) 32

Q.3 In steady flow of a compressible fluid through a pipe, the density, area and velocity at a particular section are 1.5 kg/m^3, 0.5 m^2 and 3 m/s, respectively. At another section the density and area are 0.75 kg/m^3 and 1.0 m^2 respectively. What is the velocity at this section?

(a) 1.5 m/s          (b) 3.0 m/s           (c) 4.5 m/s          (d) 6.0 m/s

Q.4 A pipe network consist of a pipe of 60 cm diameter and branches out at a point F into two branches, one of 30 cm diameter and the other of 45 cm diameter. These branch pipes rejoin at a point B. The velocity in the first branch (of 45 cm diameter) is 1.5 m/s. Which one of the following statements is true?

(a) The velocity in second branch is 1.0 m/s

(b)  The velocity in second branch is 2.25 m/s

(c) The velocity in second branch is 0.667 m/s

(d) The potential drop between F and B in both branches is same

Q.5 A compound pipe (new cast iron) system consists of pipes of length 1800 m and diameter 50 cm, length 1200 m and diameter 40 cm and length 600 m and diameter 30 cm connected in series. The equivalent length of 40 cm diameter pipe will be nearly

(a) 4300 m                   (b) 4400        (c) 4500 m               (d) 3600  

                                            Happy Learning

Target GATE & ESE 2022 (Irrigation Engineering)

 Q.1 Assertion(A): Duty is an expression of the irrigation capacity of a unit volume of water.

        Reason(R): Duty at the head of a distributary will be less than that at the head of a watercourse and more than that at the head of a canal.

(a)               (b)                (c)                  (d)

Q.2 The delta for a crop having base period 120 days is 70 cm. What is the duty in hectare/cumec

(a) 2480        (b) 1481          (c) 148        (d) 1.481

Q.3 The CCA for a distributary is 200000000 m^2. The intensity of irrigation for a crop is 40%. If KOR water depth and KOR period for the crop are 14 cm and 4 weeks, respectively, the peak demand discharge (in cumec)

(a) 2.63          (b) 4.63          (c) 8.58        (d) 11.58

Q.4 The two columns below show some parameters and their possible values:

     Parameters                                        Value 

P.        GCA                                          i. 1000 ha/cumec

Q. Permanent wilting point                 ii. 6 degree centigrade

R. Duty of canal water                        iii. 1000 hectares

S. Delta of wheat                                iv. 1000 cm

                                                             v. 40 cm

                                                            vi. 0.12

Which of the following options matches the parameters and the values correctly?

(a) P-i, Q-ii, R-iii, S-iv

(b) P-iii, Q-vi, R-i, S-v

(c) P-i, Q-v, R-vi, S-ii

(d) P-iii, Q-ii, R-v, S-iv

Q.5 The total irrigation depth of water required by certain crop in its entire growing period (150 days) is 25.92 cm. The CCA  for a distributary channel is 100,00 ha. The distributary channel shall be designed for a discharge

(a) less than 2 cumecs

(b) 2 cumecs

(c) 20 cumecs

(d) more than 20 cumecs

Target GATE & ESE 2022 (Fluid Mechanics)

 Do you know?

👉Pressure gradient in the direction of flow (∂p/∂x) is equal to the shear gradient normal to the direction of flow (∂τ/∂y).

                                            ∂p/∂x  =   ∂τ/∂y        

👉 Hele Shaw Flow: Laminar flow between parallel plates

      Stoke's Law: Settling of fine particles

      Hagen Poiseuille Flow: Laminar flow in tubes/pipes

👉Bulk modulus(k) is a measure of compressibility of fluid. It is the ratio of change in pressure (△P) to change in volume per unit volume (∆V/V). It is also called ratio of pressure to volumetric strain.

👉 Various factors that affect bulk modulus:

    > As pressure of fluid increases, bulk modulus of elasticity of fluid increases.

    > With increase in temperature of a liquid the bulk modulus of liquid decreases.

    > With increase in temperature of a gas the bulk modulus of gas increases

.👉Streak line is formed by continuous introduction of dye or smoke from a pont in the flow.

👉 For steady flow ⟶ Stream line, Path line and Streak line are same.

👉Cauchy-Riemann Equation 

> Velocity potential function exists only for irrotational flow.

> Stream function exists both for rotational & irrotational flow.

> Both velocity potential and stream function for irrotational flow satisfies laplace equation.

> For irrotational incompressible flow 

               u = -∂Φ/∂x = -∂Ψ /∂y

               v = -∂Φ/∂y = ∂Ψ /∂x

👉Flow Net

◘ A line along which stream function is constant is called stream line (ψ = Constant)

◘ A line along which velocity potential is constant is called equipotential line ( Φ = constant)

◘ A grid obtained by drawing series of equipotential lines and stream lines is known as flow net.

◘Flow net is drawn in such a way that difference between stream function stream function of two successive stream lines are same. Discharge between two successive stream line is constant in a flow net.

 

👉 Methods of drawing Flow Net

◘  Analytical method

◘  Hydraulic models

◘ Graphical method

◘ Electrical analogy method

👉 Use of Flow Net

◘  Determine uplift pressure on the bottom of a dam

◘  Loss of flow due to seepage in earth dam  

◘  Determine the stream line and equipotential lines.

    

                                                    Happy Learning

    

     

Target GATE & ESE 2022 (Irrigation Engineering)

 Do You Know ?

👉 Sprinkler system causes interference in farming operation because of its network system.

👉 In border strip method size of strip depends on soil properties. Border strip method is a controlled type of surface irrigation method.

👉 Soil moisture tension is defined as the sum of the moisture tension and osmotic pressure of soil solution.

👉  Soil moisture tension at permanent wilting point generally ranges from 7-32 atm

👉    Soil                  EC (milli-mhos/cm)            ESP (%)                        PH 

         Saline                             >4                               <15               less than equal to 8.5

        Alkaline                          <4                                <15                         8.5 - 10

     Saline-Alkaline                  >4                               <15              approximately equal to 8.5

               ESP = exchangeable sodium percentage

               EC = Electrical Conductivity

👉 Water application efficiency is the ratio of volume water stored in root zone to Volume of water supplied to root zone

👉 Garret's diagram is a graphical representation to obtain canal design parameters based on

         (i) Kennedy's theory

        (ii) Kutter's formula

Purpose: To save time and to avoid repetitive enormous calculations

👉Balanced Depth : Balanced depth of cutting canal is when volume of cutting is equal to volume of filling (Most economical way as transportation expenses of soil is minimized)

Target GATE & ESE 2022 (Geotechnical Engineering)

 Q.1 In a direct shear test, the shear stress and normal stress on a dry sand sample at failure are 0.6 kg/cm^2 and 1 kg/cm^2 respectively. The angle of internal friction (in degree) of the sand will be nearly

(a) 25            (b) 31            (c) 37            (d) 43

Q.2 In a Mohr's diagram, a point above Mohr's envelope indicates

 (a) Imaginary condition                               (b) Safe condition      

 (c) Imminent failure condition                    (d) Condition of maximum obliquity

Q.3 In the CD test on a saturated soil sample, pore water pressure is zero during

(a) Consolidation stage only                              (b) Shearing stage only

(c) Both consolidation and shearing stages       (d) Loading stage

Q.4 Assertion (A) : In box shear test, the failure plane is predetermined and is horizontal

      Reason (R) : The shear stress is applied in the vertical direction.

(a)                (b)                    (c)                (d)

Q.5 The effective stress friction angle of a saturated cohesionless soil is 38 degree. The ratio of shear stress to normal effective stress on the failure plane is

(a) 0.781         (b) 0.616            (c) 0.488         (d) 0.438

Q.6 A direct shear test was conducted on a cohesionless soil specimen under a normal stress of 200 kN/m^2. The specimen failed at a shear stress of 100 kN/m^2. The angle of internal friction of the soil (degree) is

(a) 26.6            (b) 32.6           (c) 30       (d) 29.5

Q.7 If the effective shear strength parameters of a soil are c' = 10 kPa, and Effective angle of friction = 30 degree, the shear strength on a plane within the saturated soil mass at a point where the total normal stress is 300 kPa and pore water pressure is 150 kPa will be 

(a) 90.5 kPa     (b) 96.6 kPa         (c) 101.5 kPa          (d) 105.5 kPa 

Target GATE & ESE 2022 ( Building Material)

 Do You Know?

👉Tensile strength of concrete is 10% of its compressive strength.

👉Cube compressive strength of concrete obtained from 15 cm cube is higher than 15 x 30 cm cylinder compressive strength. 

👉The specific surface (in cm^2/gm) of aggregate is inversely proportional to the particle size.

👉Air entrainment increases workability of fresh concrete.

👉Cube Strength > Cylinder strength > Modulus of rupture > Split tensile strength

👉Curing of concrete shall be done at 27 Plus minus 2 degree centigrade.

👉Slump test is suitable for concrete of medium to high workability, compacting factor test is more accurate than slump test, especially for concrete mixes of medium and low workability.

👉Vee-bee test is suitable for stiff concrete mixes having low and very low workability.

Target GATE & ESE 2022 (Geotechnical Engineering)

 Do You Know?

👉Sand drains reduces the length of drainage path resulting in acceleration of consolidation.

👉High volume change in clay is due to presence of Montmorillonite clay.

👉Loose sand and normally consolidated clay (OCR = 1) have similar stress strain curve in triaxial compression.

👉Dense sand and over-consolidated clay (OCR>1) have similar stress strain curves.

👉Stoke's Law: Sedimentation of soil particles in water with a constant velocity is known as terminal velocity.

            Stoke's Law is applicable for spheres of diameter between 0.2 mm and 0.0002 mm

👉Terzaghi's theory of consolidation considers only primary consolidation and not valid for secondary consolidation.

👉Final consolidation(Ultimate consolidation settlement) does not depend upon drainage conditions.

👉Coefficient of consolidation is inversely proportional to liquid limit.

 👉Compression index of clay is related to its index properties, especially the liquid limit

       According to Terzaghi and Peck

                Cc = 0.009 (L.L-10)      for undisturbed soils

👉The compression index for the over consolidated clay stratum (which is called as recompression index) is smaller as compared to other given soils.

👉When a soil is heavily over-consolidated its stress-strain curve has a sharp peak. It shows brittle behaviour.

 

Target GATE & ESE 2022 (Fluid Mechanics)

 Do you know ?

👉Dynamic viscosity of water is approximately 50 times that of air, but density water is around 850 times more than air so kinematic viscosity of air is more than that of water 

👉 Dynamic viscosity is the property of a fluid in motion.

👉Cavitation occurs when pressure falls below vapour pressure

👉Poise is the unit of dynamic viscosity. (1 poise = 0.1 N-s/m^2 =  Dyne-s/cm^2)

👉Vorticity and stream function parameters exist both in rotational and irrotational flows.

👉Velocity potential function exists only for ideal flow and irrotational flow.

👉Rotation of fluid is always associated with shear stress, because the rotation can be caused only by a torque exerted on the fluid particle and this will be produced by shear force.

👉Flow of blood in veins and arteries occurs as a viscous flow hence laminar.

👉Bernoulli's equation applicable for flow:

            > along a stream line.

            > for steady flow.

           > for incompressible flow.

          > when the effect of viscosity is neglected.

👉Euler's equation is based on momentum conservation, not mass conservation.

👉Couette flow: when one plate is moving and other is at rest

👉 Rouse has developed a criterion for the stability of laminar flow at any point

                              ϰ (chi) = y²ρ (du/dy)/µ

    

      

          

Target GATE & ESE 2022 (Geotechnical Engineering)

 Q.1 Consider the following statements regarding Coulomb's theory of earth pressure:

1. It is based on wedge theory of earth pressure.

2. It assumes the wall surface is smooth

3. Back face of the wall should be inclined.

Which of these statements are correct?

(a) 1, 2 and 3      (b) 1 only     (c) 2 and 3 only           (d) 3 only

Q.2  When a vertical face excavation was made in a clayey silt having density of 20 kN/m^3, it failed at a depth of excavation of 4m. What is the cohesive strength (in kN/m^2) of the soil, if its angle of internal friction was 30 degree?

(a) 23.1     (b) 20.0                (c) 11.6             (d) 10.2 

Q.3 The wall friction of retaining wall:

(a) decreases active earth pressure (AEP) but increases passive earth pressure (PEP)

(b) decreases PEP but increases AEP

(c) decreases both AEP and PEP

(d) increases both AEP and PEP

Q.4 The nature of earth pressure above dredge line behind a cantilever sheet pile wall is

(a) active        (b) passive             (c) At rest              (d) active and passive

Q.5 Assertion (A): The state of earth pressure at rest is the state of equilibrium with zero strain condition.

Reason (R): In rest condition neither the wall nor the soil moves. 

Target GATE 2022 (Fluid Mechanics)

 Q.1 In a 4 cm diameter pipeline carrying laminar flow of a liquid with dynamic viscosity = 1.6 centipoise, the velocity at the axis is 2 m/sec. what is the shear stress midway between the wall and the axis (in N/m^2) is

(a) 0.01        (b) 0.0125        (c) 0.0175         (d) 0.02

Q.2 The velocity distribution in a laminar flow adjacent to a solid wall is given by u = y-y^2. The viscosity of fluid is  5 poise. What is the shear stress (in N/m^2) at a section y = 0.05 m?

(a) 6.1          (b) Zero             (c) 12.3           (d) 0.45

Q.3 Water of kinematic viscosity = 1 centistoke flows through a 1 cm diameter pipe. Critical flow will correspond to a discharge of approximately (in l/s)is

(a) 0.008        (b) 0.013         (c) 0.016            (d) 0.025

Q.4 For laminar flow between parallel plates separated by a distance 2h, head loss varies 

(a) directly as h          (b) inversely as h      (c) directly as h^2   (d) inversely as h^3

Target GATE 2022 (Irrigation Engineering)

 Q.1 For an irrigated field having field capacity = 30%, P.W.P = 10%, permissible depletion of available water = 40%, dry unit weight of soil = 14.7 kN/m^3 and effective rainfall = 30 mm, what is the net irrigation requirement per meter depth of soil?

(a)  300 mm              (b) 150 mm        (c) 120 mm       (d) 90 mm

Q.2 Consider the following statements:

Irrigation water has to be supplied to the crops when the moisture level falls

1. below field capacity

2. to wilting point

3. below wilting point

Which of the above statements is/are correct?

(a) 1                       (b) 2 only                (c) 3 only                   (d) 2 and 3

Q.3 The total number of independent equations that from the Lacey's regime theory is

(a) 2               (b) 3                (c) 4             (d) 5

Q.4 A channel designed by Lacey's theory has a velocity of 0.88 m/sec. The value of hydraulic radius for canal carries silt of medium size 0.025 cm is

(a) 1.95 m             (b) 2.2 m            (c) 1.63 m                 (d)1.50 m

Q.5 The Electrical conductivity of medium saline water (C2) at 25 degree centigrade is of the order (in micro mhos/cm)

(a) 50 to 100         (b) 100 to 250          (c) 250 to 750        (d) 750 to 2250

Target Gate 2022 (Fluid Mechanics)

 Q.1 Match List-I with List-II and select the correct option:

          List-I                            List-II

1. Venturimeter                  A. Flow rate

2. Currentmeter                 B. Flow velocity

3. Piezometer                    C. Flow pressure

(a) A-1, B-2, C-3           (b) A-2, B-1, C-3         (c) A-3, B-2, C-1              (d) A-3, B-1,C-2

Q.2 The limit of the values of the coefficient of discharge of venturimeter is between:

(a) 0.60 to 0.75           (b) 0.76 to 0.80               (c) 0.81 to 0.94                (d) 0.95 to 0.99

Q.3 A pitot tube (coefficient =1) is used to measure the velocity of air of mass density 1.2 kg/m3. If the head difference in a vertical U-tube filled with water is 12 mm then the velocity of air (in m/s will

(a) 10                          (b) 14                              (c) 17                                (d) 20

Q.4 The head loss at an orifice (Cv = 0.98) discharging under a head of 2 m is:

(a) 0.02 m                   (b) 0.04 m                     (c) 0.06m                             (d) 0.08m

Q.5 The viscosity of water as compared to that of air is about

(a) 50 times                 (b) 55 times                   (c) 60 times                         (d) 65 times