Geotechnical Engineering

 👉Casagrande apparatus: used to determine liquid limit.

👉 Oedometer is used to find the consolidation characteristic of soil.

👉 Hydrometer is used to determine grain size distribution

👉 Plate load test is used to determine safe bearing capacity of soil.

👉Pycnometer method is the laboratory method for determining specific gravity as well as water content of soil sample

👉Permeameter is used to find hydraulic conductivity and permeability of soil sample.

👉Core cutter is a field method to compute bulk density of soil.

👉 Increasing order of their grain size:

         Montmorillonite < Illite < Kaolinite

👉Sequence of plasticity index

    Montmorillonite > Illite > Kaolinite

👉 Relative compaction: Degree of compaction achieved as a percentage of the laboratory compaction

       Relative compaction = dry density in field/ maximum dry density from the proctor test 

👉Relative density can be zero but relative compaction can never be zero.

👉with increase in temperature, viscosity decreases and permeability increases.

                     k ∝ Unit weight/ Viscosity

👉Effective stress increases, void ratio decreases and permeability decreases.

 👉Organic matter has the tendency to move towards flow channel and choke them, thus reduces permeability

👉 Entrapped air decreases the permeability of soil.

 

Engineering Hydrology

 👉 A flow duration curve is a plot of discharge against the percentage of time the flow was equaled or 

exceeded. This curve is also known as discharge frequency curve.  

👉Line joining points of equal rainfall depth is called isohyet.

👉 Isopleths are line on a map through points having equal depth of evapotranspiration.

👉                    Name                       Isopleth of (i.e line joining places of equal)

                        Isotherm                                           Temperature

                         Isobar                                               Pressure

                 

                         Isobath                                             Depth in sea

 

                        Isochrone                                        Travel time from a common centre

                       Isohaline                                              Salinity

                        Isohyets                                                 Rainfall

                        Isonif                                                Snowfall amount

                       Isoryme                                                Frost

                        Isohels                                                Sunshine

👉  Bowen's ratio is defined as the ratio of Sensible heat transfer from water surface to air (Ha) to Heat energy used up in evaporation (He)

👉               Property                                  Measuring Instrument

                  Evapotranspiration                          Lysimeter

                Capillary Potential                            Tensiometer

                Transpiration                                    Phytometer

                 Evaporation                                     Atmometer

                Hydraulic Conductivity                     Permeameter

                Infiltration Capacity                          Infiltrometer

                                                                           Rainfall Simulator

              Humidity                                             Hygrometer

              Relative Humidity                              Psychrometer

              Wind Speed                                        Anemometer

 👉 Ratio of total channel length to the discharge area is called drainage density. 

👉         Hyetograph:  Rainfall intensity versus time 

   

               Mass Curve: Cumulative rainfall versus time

               Hydrograph: A hydrograph is a graph showing the rate of flow versus time past a specific point in a river, channel, or conduit carrying flow

Target GATE & ESE 2022 (Building Materials)

 👉Fine grinding leads to high early strength.

👉 The finer the cement the higher is the rate of hydration which results in early development of strength.

👉Decreasing the lime cement increases the proportion of C2S (Belite) and reduces that of C3S (Alite) and hence leads to slow setting low heat cement.

👉Burning at higher temperature increases the proportion of Alite (C3S) in cement and hence leads to high early strength.

👉Increasing the quantity of gypsum retards setting of cement.

👉Before testing setting time of cement, test for consistency (Normal Consistency) is done to know the water required for preparation of standard paste of normal consistency. Amount of water (0.85 times water used in consistency) is used for preparation of cement paste in setting time test.

👉Low heat cement has a high percentage of dicalcium silicate (C2S) and low percentage of tricalcium silicate (C3S)

👉High early strength portland cement has high percentage of C3S and lower percentage of C2S

👉Specific gravity of cement (G = 3.14) is determined by Le Chatelier's Flask.

                                                                 Le Chatelier's Flask

👉For checking the soundness( Soundness test is done on cement to determine the expansion of cement due to the presence of free lime and magnesia in the cement) of cement Autoclave test is done.

    

👉The fineness of cement is determined by Blaine's Air Permeability apparatus.

👉Superplasticizers increases the workability by dispersion of cement particles. It can remove air bubbles . It can also be used to retard setting.

👉Blast furnace slag cement is more resistant to sulphate attack and is specified for marine work or pipe carrying water containing chemicals or sewage.

👉  Different Phase of cement                          Temperature ( in Degree Celsius)

      Formation of C3S                                                               > 1250 

   

       Formation of C2S                                                               900-1200

      Formation of C3A and C4AF                                              Cooling Stage

      Decarbonation of CaCO3                                                     < 900

👉LSF(Lime saturation factor) is a used quality parameter to limit the amount of free lime (CaO)

👉LSF is used a quality parameter to limit the Unsoundness of the cement.         

👉 Crystal Structure of different phases

             C3S ------------------  Irregular Structures, several polymorphs.

         

             C2S--------------------Rounded structures, several polymorphs

             C3A ------------------Cubic in pure form

             C4AF-----------------Series of solid solutions

👉 The decreasing order of heat of hydration of pure cement compounds are:

                 C3A > C3S > C4AF > C2S

Geomatics Engineering

 👉Actual Distance = (Measured Distance/Nominal length of chain) x Actual length of chain

👉Offsets are lateral measurements made w.r.t main survey line which may be oblique or perpendicular in nature.

👉In aerial photogrametery the photographs are taken at proper interval to provide generally 60% longitudinal overlap and 30 % side overlap.

👉The tape corrections used in Surveying

• Correction for Standardization (+ or -)
• Correction for Slope (Always negative)
• Correction of Pull (+ or -)
• Correction for Temperature (+ or -)
• Correction for Sag (Always negative)
• Normal Tension 
• Correction for Misalignment (Always negative)

👉 Tape correction for standardization (Csd):

                            Csd = (l'-l)/l x L

where, l = nominal length of tape
          l’ = actual length of tape

          L = measured length

          Csd = Correction for standardization

 👉 Correction for Slope (Cs):

        

Where,

                    D = horizontal equivalent
                    L = slope distance
            

                        

     Where,          h = difference in elevations of the end points

                           Cs = correction due to slope

 

👉 Correction for Pull (Cp):

The correction of pull is computed as

Where,
P = pull applied during measurement.
Po = Standard pull
L = Measured length
A = Cross- sectional area of the tape
E = Young’s modulus of material of tape

👉Correction for Temperature (Ct):

The correction for temperature is computed as

Ct = α (Tm - To) L

where,
α = coefficient of linear expansion
Tm = Mean temperature of the tape
To  = Standard temperature

👉 Sag Correction (Csg):

• A tape is supported at two ends, it takes the shape of a CATENARY. 
• The correction for sag should be applied as the horizontal chord Length is always shorter than the curved length

Where,
W = Weight of tape per unit length.
P = Applied pull.
l1 = length of the tape suspended between the supports.

The above equation can also be written in the form of total weight of tape

where,
W = total weight of tape between the supports

👉 Normal Tension:

The normal tension is a tension at which the effects of pull and sag are neutralized.

     

👉Correction for Misalignment (Cm):

•  If L1 = L2 then Cm = d² / L (Negative)

👉Optical square is used to establish two points at right angle. The principle used is double reflection.

👉Method commonly used in Reconnaissance surveying for measurement of horizontal distance are PACING, PASSOMETER, PEDOMETER, ODOMETER,MEASURING WHEEL, SPEEDOMETER,PERAMBULATOR.

👉Equation of cubic parabola  = X^3/6RL

👉Shift in Transition Curve = L^2/24R

Environmental Engineering

 👉Typical range of Hydraulic Conductivity are as follows:

   Soil classification of an aquifer      Hydraulic Conductivity (m/day)          Drainage Characteristics 

         Gravel                                            100-1000                                                Pervious

          Sand                                               1-10                                                      Pervious

         Silt                                                  0.1-0.01                                                 Slightly Pervious

        Clay                                                 10^-5 to 10^-6                                      Impervious

👉 Components of Water Demand:

     Domestic Demand     :         135 lpcd (litre per capita per day)

    Public Demand           :         20 lpcd

  Industrial Demand        :         50 lpcd

  Commercial Demand   :         20 lpcd

       Fire Demand           :          15 lpcd

      Loss and waste         :          50 lpcd 

       Total =  270 lpcd

👉Fire Fighting Water Demand

👉 Fire Fighting Water Demand Empirical Formulae:

• Buston's Formula
• Kuichling's Formula
• Freeman's Formula
• National Board of Fire Underwriter's Formula

       

👉 Population Forecasting Methods:

• Arithmetic Increase Method
•  Geometric Increase Method
•  Incremental Increase Method
•  Logistic Curve Method
•  Growth Composition Analysis Method
•  Master Plan Method
•  Decreasing Rate of Growth Method
•  Simple Graphical Method
•  Comparative Graphical Method
•  Ratio Method

Solid Mechanics

 👉Plane having principal stress has no tangential stress.

👉Mutually perpendicular planes are 180 degree apart in Mohr circle and have numerically equal value of shear stress.

👉Maximum shear stress = radius of Mohr's circle

👉         Theory of Failure                                               Also Known as  

       Maximum principal stress theory             Rankine theory, Lame's theory, Maximum stress theory

        Maximum principal strain theory                             St. Venant theory

           Maximum shear stress theory                   Tresca theory, Guest theory, Columb theory

          Maximum strain energy theory                              Beltrami Haigh theory

      Maximum shear strain energy theory                 Distortion energy theory, Von-Mises theory

👉 Bending Equation 

                                  M/I = σ/y  = E/R

where, M = Bending Moment

           σ  = Bending stress

           I =  Moment of inertia

          y = Distance of the fibre from Neutral axis

         R = Radius of curvature

         E = young's modulus of elasticity

👉 Torsion Equation:

                      T/Ip = τ/r = τmax/R  = N.θ/l

👉 Strain energy per unit volume = 1/2 x shear stress x shear strain

👉 Strain energy in torsion = 1/2 x T x θ

👉  For Brittle materials, Normal stress theory gives best result

👉 For ductile material maximum shear stress theory is applicable.

                                                                Happy Learning

Design of Steel Structure

 👉 Steel's modulus of elasticity is about 3 times that of Aluminium.

👉 Coefficient of thermal expansion for aluminium is about twice that for steel.

👉 Aluminium requires less maintenance than steel as steel prone to rusting

👉Strength to unit weight ratio of aluminium is higher than that for steel.

👉As per IS 800-1984 Cl 9.1.3 members subjected to heavy impact and fatigue shall not be designed on basis of plasticity theory, as it makes full use of materials strength beyond elastic limit.

👉 Truss carries axial load and that can cause shortening.

👉Beam carries force by bending.

👉Column resist force as axial load which can cause buckling of column.

👉Shaft carries force by twisting.

👉According to IS 800-1984 Following are the limits for slenderness ratios

• For compression member carrying dead and super imposed loads =180
• For members carrying compressive loads due to wind or seismic forces only =250
• For members carrying tension but in which the reversal of stress occurs due to wind and seismic forces = 350

👉Permissible axial tensile strength = 0.60 fy

👉Permissible shear stress = 0.45 fy

👉Permissible bearing stress = 0.75 fy

👉Permissible stress in slab base = 185 MPa for all steels

👉Allowable maximum average shear stress = 0.40 fy.

                                                            HAPPY LEARNING

Engineering Hydrology

 👉The hydrological budget equation is:

                          P-R-E-T-G = △S

Where, P = total precipitation

             R = Net runoff = R2-R1 = surface runoff flow- surface runoff inflow

            E = Total evaporation

            T = total Transpiration

          G = Net ground water flow

         △S = Total storage increase

 👉 Hydrological cycle is the cycle in which water is transported from the oceans to the atmosphere as vapours, from the atmosphere to the land as precipitation and back from land to oceans as runoff.   

👉Drizzle:  A fine sprinkle of numerous water droplets of size less than 0.5 mm and intensity less than 1 mm/h

Rain: The precipitation of liquid water with drops of sizes larger than 0.5 mm 

Hail: It is showery precipitation in the form of irregular pellets or lumps of ice of size more than 5 mm.

👉 Average rainfall over a catchment area can be estimated as

1. Arithmetic mean method: 

• every rain gauge station is given equal weightage regardless of its location.
• Rainfall is almost uniformly distributed over the whole catchment area which rarely occurs in nature.
• method is fast but does not give accurate results.

2. Theissen polygon method: 

• In this method weightage to the various rainfall datas based on area close to the rain gauge station 
• Method is fast when once the weights are known
• It does not take care of the variability in rainfall due to elevation difference(topographical influence are not take care of)
• New polygon is required to be drawn when due to addition or deletion of raingauges to the network, weight of each station changes.

3. Isohyetal method :

• This is most accurate method
• It utilizes all relevant data's and properly interpret them.
• method is slow and laborious

4. Normal ratio method: 

• It is used to estimate missing rainfall data.

Geotechnical Engineering

 👉 Active earth pressure in loose state is larger than the active earth pressure in dense state.

👉 Passive earth pressure in dense state is larger than the passive earth pressure in loose state.

👉 By compacting the soil, active earth pressure decreases but passive earth pressure increases.

👉Soils deposited by wind are called Aeolian soil.

👉All types of soils carried and deposited by water are known as Alluvial deposits.

👉Lacustrine soils are soil deposited in lake beds.

👉Marine deposits are formed when the flowing water carries soils to oceans or sea.

👉Loess is a loose deposit of wind blown silt that has been weakly cemented with calcium carbonate and montmorillonite.

👉Marl is a very fine grained calcium carbonated soil of marine origin.

👉Peat is a highly organic soil, consisting almost entirely of vegetative matter in varying states of decomposition, brown to black in colour, possessing an organic odour.

👉Peat and Muck are organic clay.

👉Volume of solids will remain same in fill and borrow pit.

👉For a sandy soil with soil grains spherical in shape and uniform in size the theoretical void ratio is 0.91.

Combined State Engineering Services (General Recruitment/Special Recruitment) Examination-2021 (UPPSC)

 

UNION PUBLIC SERVICE COMMISSION (UPSC) PROGRAMME OF EXAMINATIONS/RECRUITMENT TESTS (RTs) -2022

 

Target GATE & ESE 2022 (Strength of Material)

 👉Elongation in prismatic bar 

                        △ = ү.L^2/2E

                        △ = WL/2AE

Here, △ = elongation in prismatic bar

           L = length of bar

           W = self weight of the bar = ρ.A.L

          E = young's modulus of elasticity

          ү = Unit weight of material

👉 Elongation in conical bar

               ∆ = ү.L^2/6E

👉 Elongation in conical bar due to self weight is one third of elongation in prismatic bar due to self weight. 

👉 Important Relationship

    E = 2N (1+μ)

   E = 3K(1-2μ)

   μ = (3K-2N)/(6K+2N)

   E = 9KN/3K+N

where,

        N = Modulus of rigidity/Shear Modulus

        K = bulk modulus

        E = Modulus of elasticity/ Elastic modulus

        µ = Poisson's ratio ( 0 to 0.50)

👉   Modulus of Resilience is energy stored upto elastic limit per unit volume.

👉       △Sudden = 2.△static

👉 strain is the fundamental behaviour but stress is a derived concept because strain can measured with some instrument  and is a fundamental quantity however stress can only be derived , it can not be measured.

👉 If loading of nth degree, then shear force diagram is of (n+1) degree and bending moment diagram  is of (n+2) degree

👉For bending moment M to be maximum

     dM/dx =0 and we know dM/dx  = Shear force (V)

    Bending moment is maximum at the section where shear force is zero or changes sign.

👉        dM/dx = V       (Slope of Bending moment = shear force)

             dV/dx  = w        (Slope of shear force = loading intensity)

             M = ∫ V dx

             V  = ∫ w dx

             d2M/dx2 = dV/dx  = w

   M = Bending moment

   V = shear force

   w = loading intensity

 👉Point of contra-flexure is the point where bending moment changes it's sign

👉        Real Beam             Conjugate Beam

        Hinged Support              Hinged Support

        Free Support                  Fixed support

        Fixed support                  Free support

        Internal roller                  Internal hinge

        Internal hinge                  Internal roller

   

                                                Happy Learning

                             

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JAM 2022 Notification

 

UPSC Examinations 2021

 

GATE 2022 Question Paper Pattern

 

GATE 2022 Notification

 

Target GATE & ESE 2022 (Geomatics Engineering)

 👉The correct sequence of the survey is

    (a) Traffic survey

    (b) Reconnaissance survey

    (c) Preliminary survey

    (d) Detailed survey or location survey

👉Topographical survey is done to determine information about man made and natural features on earth surface including their elevations.

👉Reconnaissance survey is a kind preliminary survey which is performed to find out method of survey to be adopted and its rough cost.

👉Cadastral survey is done to establish property boundaries.

👉Archaeological survey is done to collect information about old and relic structures.

👉 Transverse surveying is done with the help of compass and chain.

👉Geodetic surveying (Curvature of earth is taken into account) is done with the help of precise instruments such as Theodolite 

👉Weddle sounding machine is used to determine depth of sea in hydrographic surveying.

👉The principal of surveying is work from whole to part.

👉 Various instruments used in surveying and their purpose:

• Pegs: To mark survey station and end points of survey lines on the ground
• Ranging Rod: For locating a number of points on a long survey line
• Offset rods: To set out offset line at right angles
• Prism Square: Setting out right angles
• Clinometer: To measure the slope of ground
• Optical Square: To set out right angles
• Prismatic Square: Advanced version of Optical Square and used to set out right angles
• French Cross Staff: Used to set out either 45 degree or 90 degree
• Open Cross Staff: Type of cross staff which is also used to set out 90 degree
• Theodolite: To measure of all horizontal and vertical angles
• Dumpy Level: Measurement of angle and elevation
• Auto Level: For Levelling purpose

                                                                    Fig 1.  Optical Square

                                                              Fig.2 French Cross Staff

👉Offsets are lateral measurement made w.r.t main survey line which may be oblique or perpendicular in nature.

👉The main objectives of cross staff survey is:

• To locate boundaries of an area
• To plot the figure to a scale
• To find area of the piece of land to be surveyed.  

👉Methods commonly used in reconnaissance surveying for measurement of horizontal distance are:

• Pacing
• Passometer
• Pedometer
• Odometer
• Measuring wheel
• Speedometer
• Perambulator

                                                                  Fig 3. Passometer

  

 Fig 4. Pedometer

Happy Learning

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Target ESE 2022 (Basics of Material Science & Engineering)

 👉Atoms are made of electron, proton and neutrons. 

👉 Electrons and protons are negative and positive charged particles respectively. The magnitude of each charged particle in an atom is 1.6 x 10^-19 Coulombs.

👉The mass of electron is negligible as compare to proton and neutron.

👉The unit of mass is an atomic mass unit

          1 a.m.u = 1.66 x 10^-27 kg 

👉Matter is composed of tiny particles called atoms.

   1. Stable particles: Electron, proton and neutron

   2. Unstable particles- positron, neutrino, anti-neutrino and meson

   3. Composite particles- Deuteron and alpha- particles

👉Electron: It carries a very small negative electrical charge.

                      It has negligible mass i.e. its mass is 1/850th of the mass of hydrogen atom.

👉Proton: It carries small positive electrical charge. 

                   Mass of each proton is same as that of hydrogen atom.

                   Protons are also present in all all the atoms.

 👉Neutron: It does not carry any electrical charge. Its mass is equivalent to that of proton.

👉 Positron or positive electron: The positron or antielectron is the antiparticle or the antimatter counterpart of the electron. The positron has an electric charge of +1 e

👉Meson: The mass of meson is in between the mass of electron and proton.

                   Mesons were discovered during cosmic ray studies.

👉 There are two types of meson (i) p-meson which is heavier (ii) m-meson which is light

👉Both type of mesons may be either negatively or positively charged.

👉Deuteron: It is positively charged.

                      It is heavy hydrogen nucleus.

 👉 Alpha Particles: They are double charged helium nucleus.

                                    They appear as product of radioactive decay.

👉Meson carries a either negative or positive charged.

👉The weight of an electron is 1/1836 of the weight of proton or neutron.

👉Avogadro Number(N) = 6.023 x 10^23

👉Mean distance between atoms in the range of 0.23 nm.

                                                                    Happy Learning

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Target ESE 2022 ( Basics of Energy and Environment)

👉 Ecology: Study of ecosystem. 

👉Ecosystem: It was coined by A.G Tansley

👉Environment: Everything that surrounds or affects an organism during its life time is collectively known as its environment. It comprises both living (biotic) and non-living (abiotic) components.

👉Components of Environment  

             Abiotic (Non-living)                                     Biotic (Living)

               Energy                                                          Green plants

              Radiation                                                      Non-green plants

          Temperature & heat flow                                 Decomposers

                Water                                                             Animals

                 Soil                                                                  Man

👉When an ecosystem is healthy (i.e. sustainable) it means that all the elements live in balance and are capable of reproducing themselves. Ecosystem can be as small as a single tree or as large as entire forest.

👉Types of ecosystem

        (i) Natural                        (ii) Artificial (e.g.  Zoo, aquarium, gardens)

👉 Natural ecosystem can be classified as

       (a) Terrestrial (e.g. Forests, Grasslands, deserts)      (b) Aquatic (e.g.  Lakes, Rivers, Oceans, Ponds)

👉Ecotone: Transition zone between two different zones of ecosystem.(Ecotone is a zone of junction between two or more diverse ecosystems)

e.g. Mangrove forests represent an ecotone between marine and terrestrial ecosystem

 

👉In the Ecotone region , population densities of certain species is greater than adjoining regions. This phenomenon is called Edge Effect.

e.g. Coastal region, wetlands

👉 Characteristics of Ecotone

• It may be very narrow or quite wide
• It has the conditions intermediate to the adjacent ecosystems. Hence it is a zone of tension
• It is linear
• A well developed ecotones contain some organisms which are entirely different from that of the adjoining communities. 

             

                          

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Target GATE & ESE 2022 (Building Materials)

 Do you Know?

👉Blaine's Air Permeability apparatus is used to test fineness of cement.

                                        

                                                    Fig 1. Blaine Air Permeability apparatus

👉Vicat's needle is used to determine the setting time of cement.

                                                               Fig 2. Vicat's Apparatus

👉Soundness of cement is determined by Le-Chatelier apparatus.

 

Fig 3. Le-Chatelier Apparatus

👉According to IS 4031 Part 5, the initial setting time is conducted on cement by gauging the cement with 0.85 times the water required to give a paste of standard consistency.

👉Low heat portland cement can be used for mass concreting in very large structure while rapid hardening portland cement is unsuitable for it.

👉Gypsum is used in the cement grouts for retarding the setting time.

👉According to IS code for an ordinary portland cement (OPC), the initial setting time should not be less than 30 minutes and the final setting time should not be more than 10 hours (600 minutes)

👉Fine grinding leads to high early strength.(the finer the cement the higher is the rate of hydration which results in early development of strength.)

👉The temperature range in a cement kiln is 1300 to 1500 degree centigrade.

👉Specific gravity of cement is determined by using Le Chatelier's flask.

👉In OPC following are the proportion of oxides

                 Cao  ----------  63%

                SiO2 ----------- 20%

                Al2O3----------- 6.3%

               Fe2O3------------- 3.60%

               MgO-------------- 2.40%

👉 Following is the compound composition in OPC

             Compound                                  Wt %

     Tricalcium silicate, C3S(Alite)        45-60

     Dicalcium silicate,C2S (Belite)      15-30

    Tricalcium aluminate, C3A              6-12

Tetracalcium aluminoferrite, C4AF      6-8

                                                     

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Target GATE & ESE 2022 Revision Test

 Q.1 A stream function is given by ψ = 3x^2 -y^3. What is the magnitude of velocity components at the point (2,1) ?

(a) 8.52                                  (b) 9.17

(c) 10.81                                (d) 12.37

Q.2 What is the minimum size of glass tube that can be used to measure water level if the capillary rise in the tube is to be restricted to 2 mm ? (Take surface tension of water in contact with air as 0.073575 N/m)

(a) 1.5 cm                               (b) 1.0 cm

(c) 2.5 cm                               (d) 2.0 cm

Q.3 What is the hydraulic radius of a stable canal carrying a discharge 0f 27 m^3/s using Lacey's method? (Assume silt factor is unity)

(a) 1.44 m                               (b) 2.67 m

(c) 3.14 m                               (d) 4.28 m

Q.4 Which one of the following is the correct assumption of Rankine's theory?

(a) The soil mass is infinite

(b) The soil mass is non homogeneous

(c) The soil mass is cohesive

(d) The ground surface is a plane which may be horizontal or inclined

Q.5 Which one of the following is not an instrument for setting out right angles?

(a) Cross staff                        (b) Site square

(c) Prism square                    (d) Optical square

Q.6 The hardness of aggregate is tested by

(a) Impact test                      (b) Crushing strength test

(c) Abrasion test                   (d) Soundness test

Q.7 The drawback of electric seasoning of timber is

(a) Checks                      (b) Splitting

(c) Cracks                       (d) Reduced Strength

Q.8 Pozzolanas are

(a) argillaceous materials 

(b) calcareous materials

(c) accelerators

(d) siliceous materials

Q.9 A plane element in a body is subjected to a tensile stress of 100 MPa and shear stress of 25 MPa. What is the normal stress on a plane inclined at 15 degree with the tensile stress?

(a) -5.8 MPa                    (b) -4.8 MPa

(c) -3.8 MPa                   (d) -2.8 MPa

Q.10 If the pressure head of water is 100 m and specific gravity of kerosene is 0.81, what is the pressure head of kerone?

(a) 123.5 m of kerosene             (b) 241.3 m of kerosene

(c) 75.1 m of kerosene               (d) 52.4 m of kerosene

 

                                

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Target GATE & ESE 2022 (Geotechnical Engineering)

 Do You Know?

👉 In-Situ Shear modulus of soil can be calculated from Pressure-meter test.

👉 Soil Consistency                  N-Value

       Very Soft                               0-2                           

       Soft                                       3-4

      Firm                                       5-8

       Stiff                                      9-16

   Very Stiff                                 16-32

     Hard                                        >32

👉 Soil Description    Relative Density(%)    N-Value

      Very Loose               <15                                  <4

        Loose                     15-35                               4-10

Medium Dense              35-65                              10-30

   Dense                          65-85                             30-50

Very Dense                    >85                                    >50

👉  SPT: Suitable only for Cohesionless soil such as sandy soil

      DCPT: Dynamic cone penetration test is conducted by driving the cone by blows of a hammer. This is primarily used for cohesive soils but also applicable for medium to fine sand.

     SCPT: Static Cone penetration test is used for soil profiling. It also gives the value of end resistance and frictional resistance of sleeves.

👉Auger boring is most effective in soft soils which can stand unsupported and have some stickiness so that they do not fall back into hole during lifting operation.

👉Geophysical methods: They are non-destructive methods used in the construction industry for investigation of sub surface.

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Target GATE & ESE 2022 (Geotechnical Engineering)

 Q.1 If an SPT test gave the average blow count of 32 in fine sand below water table, then what is the corrected value of blow count?

(a) 22.1             (b) 23.5              (c) 24.2                (d) 24.8

Q.2 On which of the following soils is the standard penetration test useful?

A.  Cohesionless soil               B. Medium clay

C. Gravelly soils                     D. Very stiff clays

Select the correct answer using the code given below

(a) A only                           (b) A and C 

(c) A and B                        (d) C and D

Q.3 The standard penetration resistance value obtained in a deep deposit of sand at a depth of 6 m was 28. The unit weight of sand is 18 kN/m^3. What is the corrected value of number of blows for overburden pressure?

(a) 60                                (b) 57

(c) 59                                (d) 55

Q.4 Consider the following statements:

1. Standard penetration test is commonly used for cohesionless soils.

2. Standard penetration test results in respect of a cohesionless soil are correlated to its density index and friction angle.

3. Use of N-value not corrected for overburden pressure leads to highly conservative design of footing at shallow depths.

Which of the following statements are correct?

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

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

Q.5 During a sampling operation , the drive sampler is advanced 600 mm and the length of sample recovered is 525 mm. What is the recovery ratio of the sample?

(a) 0.125                         (b) 0.140

(c) 0.875                         (d) 0.143

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Target GATE & ESE 2022 (Geotechnical Engineering)

 Do You Know?

👉 For a good quality soil sampler all the parameters mentioned below should be low.

            Area ratio                       10% or less

           Inside clearance              0.5-3%

           Outside clearance           0-2%

👉 For soft sensitive clays, an area ratio of 10% or less is preferred.

👉   

• Chunk samples are considered as undisturbed samples.
• Remoulded sampler tends to disturb the soil structure completely
• Split spoon sampler is a thick tube type of an open driven sampler with an area ratio around ratio 30%, so the samples collected are of the disturbed type 
•  Piston sampler is a thin tube type sampler and excellent tool for obtaining very fine undisturbed samples, especially in soft sensitive clays.      

👉 Split Spoon sampler: Used in all types of soil. It gives disturbed but representative sample.

      

👉 Rotary Sampler: It is double walled tube sampler. The outer tube (rotating barrel) is having a cutting bit so they can be used in hard cohesive soils and rocks.

👉Stationary piston sampler: Very much suited for sampling in soft soils and saturated sands.

👉Recovery Ratio(R.R): Ratio of recovered length of sample to penetration length of sampler.

         If           R.R = 1   Good recovery

         If           R.R <1   soil in sample is compressed

         If           R.R >1   soil has swelled

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Target GATE & ESE 2022 (Fluid Mechanics)

 Do You Know?

👉

• Hot Wire Anemometer: It is used for measurement of instantaneous velocity and temperature at a point in flow but it is an ideal tool for measurement of velocity fluctuations in time in turbulent flow.
• Orifice Meter: It is cheap device which is used to measure the volume flow rate means discharge.
• Pitot Tube: Used for measurement velocity of flow.

👉     Preston Tube: Used for Boundary shear stress measurement.     

👉     Submerged broad crested weir  (Cd = 0.83 to 0.85)

👉          Free broad crested weir ( Cd = 0.85 to 1)

👉       For ogee spillway ( Cd = 1.19 Cds), where Cds is the discharge coefficient for sharp crested weir. 

👉       Cd value increases for ogee due to adhering Nappe

👉 Rehbock formula gives the expression for discharge over a rectangular suppressed weir.

                                  Q = 2/3 (0.605 + 0.08 H/Z + 0.001/H) sqrt (2g). BH^1.5 

 👉 Francis found that due to end contraction the effective width of the nappe is reduced by o.1H.

                                                              Leff = (L - 0.1 nH)

👉 Cipolletti notch (or weir) is a trapezoidal notch which gives discharge equal to the discharge that would pass over a rectangular notch. 

                                                     Q = 2/3 Cd sqrt(2g) LH^1.5

👉 Ventilation of Nappe: When there is no ventilation of nappe, discharge increases because the Nappe is pulled down due to negative pressure created in the zone below nappe.

👉  Let Q be the discharge in free Nappe then

        For depressed Nappe Qd = (1.06-1.07) Q

        For Adhering Nappe  Qa = 1.25 Q

👉 Orifice is an opening in the tank and Mouthpiece is short length of tube

👉 Coefficient of resistance of Orifice (Cr) is defined as the ratio of Loss of KE through orifice to actual KE.

                                               Cr = (1/Cv^2 -1)

      where Cv is the coefficient of velocity. 

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Target GATE & ESE 2022 (Fluid Mechanics)

 Q.1 The range of coefficient of discharge for a venturimeter is 

(a) 0.6-0.7             (b) 0.7-0.85            (c) 0.85-0.92              (d) 0.92-0.98

Q.2 A rotameter is used to measure:

(a) viscosity of fluids

(b) density of fluids

(c) flow rate of fluids

(d) rotational energy of a fluid

Q.3 Notch is a device used for measuring

(a) rate of flow through pipes

(b) rate of flow through a small channels

(c) flow velocity through a pipe line

(d) flow velocity through a small channel

Q.4 A cipolletti weir is:

(a) a rectangular weir of varying dimension

(b) a weir is designed for economical discharge

(c) a combination of a rectangular and triangular weir

(d) a trapezoidal weir whose side slopes are one horizontal to four vertical

Q.5 In a rectangular weir, the discharge varies as:

(a) H               (b) H^0.5       (c) H^1.5            (d) H^2.5

Q.6 The sheet of water flowing through a notch or over a weir is known as

(a) Nappe            (b) Crest            (c) Height of weir/notch     (d) Sill

Q.7 If the error in the measurement of head in a rectangular notch is 1% , then error in the measurement of discharge will be

(a) 1%                                                    (b) 1.5%

(c) 2%                                                   (d) 2.5%