Civil Engineering Notebook (CEN)

Solution: 1 Concept: Superelevation: ▪️It is the transverse slope to counteract the centrifugal force and to reduce the tendency of the vehicle to overturn or skid. ▪️It is the rise of the outer edge of the pavement with respect to the inner edge on a horizontal curve thus providing a transverse slope throughout the length of the horizontal curve. ▪️It is also known as cant or banking. Pothole: ▪️The appearance of bowl-shaped holes, usually after rain. ▪️This indicated progressive disintegrations of bituminous premix carpet surfacing by loss of aggregates. ▪️When a vehicle negotiates a vertical curve on a highway without super elevation the pressure on the tires on the outer edge is more than on the inner edge. Thus the chance of potholes is more on the outer edge of the road. #transportation

Q28)If super elevation is NOT provided on a horizontal curve of a highway in which portion of the road, potholes will be developed ? 1 Outer edge of road 2 Inner edge of road 3 Center of road 4 Shoulder of road

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https://youtu.be/IVxu406gtC0 SSC JE 2023 II NOTIFICATION 🔔 II MAJOR CHANGES IN PATTERN II

Solution: 4 Explanation : Infiltration: 👉Infiltration is the flow of water through the soil surface into a porous medium under gravity action and pressure effects. 👉The infiltration capacity is the maximum rate at which water can be absorbed by a given soil per unit area under given conditions. #hydro

Q24)Infiltration capacity is 1 A constant factor 2 Changes with time 3 Changes with location 4 Changes with both time and location

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📝CEN FACT📝 The horizontal angle between the True meridian and magnetic meridian is called declination. Local attraction:  Local attraction is the phenomenon by which the magnetic needle is constantly prevented to point towards the magnetic north at a place. This is because that these magnetic compass is influenced by other magnetic objects at that locality such as wires carrying electric current, rails, steel and iron structures, steel tapes etc. Magnetic Bearing:  The horizontal angle which a line makes with the magnetic meridian measured from Magnetic North line is called magnetic bearing. It varies with time.Magnetic meridian of a line can be measured in the field by using prismatic compass. Azimuth:  Azimuth of a line is its horizontal angle measured clockwise from geographic or true meridian. #survey

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Solution: 4 Explanation: Mach number (M or Ma) 👉Dimensionless quantity in fluid dynamics 👉The ratio of the flow velocity of the object to the local speed of sound. 👉If the Mach number is less than 0.3, flow can be treated as incompressible​ 📌mportant Points 👉The magnitude of the compressibility effect can be judged with the flow velocity.   👉For air, when the flow velocity is 100 m/s or less, the air is treated as an incompressible fluid. 👉If the velocity is greater than 100 m/s, the air is treated as compressible fluid. #fm

Q9)Flow of air can be considered to be incompressible within 1% error if the mach number of flow is less than _. 1) 0.4 2) 0.6 3) 0.1 4) 0.3

❄️CEN FACT❄️ Stabilization Ponds: 📌The stabilization ponds are open flow through basins specifically designed and constructed to treat sewage and biodegradable industrial wastes. 📌They provide long detention periods extending from a few to several days. 📌Pond systems, in which oxygen is provided through mechanical aeration rather than algal photosynthesis are called aerated lagoons. 📌Lightly loaded ponds used as a tertiary step in waste treatment for polishing of secondary effluents and removal of bacteria are called maturation ponds. 🔰Classification of Stabilization Ponds is as follows: 1. Aerobic ponds: 📝It is a shallow pond with a depth of less or equal to 0.5 m and BOD loading of 40-120 kg/ha/d so as to maximize penetration of light throughout the liquid depth. 📝Such ponds develop intense algal growth. 2. Anaerobic ponds: 📝It is used as pretreatment of high-strength wastes with a BOD load of 400-3000 kg/ha.d. 📝Such ponds are constructed with a depth of 2.5-5m as light penetration is unimportant. 3. Facultative ponds: 📝Facultative pond functions aerobically at the surface while anaerobic conditions prevail at the bottom. 📝They are often about 1 to 2 m in depth.  📝The aerobic layer acts as a good check against odor evolution from the pond. #enviro

Solution: 1 Concept: 📝A triaxial test is used to determine the shear strength parameter of soil. 📝The triaxial compression test consists of two stages: ❄️First stage: In this, a soil sample is set in the triaxial cell, and confining pressure is then applied. ❄️Second stage: In this, additional axial stress (also called deviator stress) is applied which induces shear stresses in the sample. The axial stress is continuously increased until the sample fails. 📝During both stages, the applied stresses, axial strain, and pore water pressure or change in sample volume can be measured. S = C̅ + σ tan ϕ Where, S = Shear strength of soil, C = Cohesion of soil, and ϕ = angle of internal friction C & ϕ are known as the Shear strength parameters of soil. Tests carried out to measure the shear strength of the soil: i) Direct shear test ii) Unconfined compression test iii) Triaxial compression test iv) Vane shear test #soil

Q96)Which test is to be conducted in the laboratory for the determination of shear strength parameters 'C' and 'ϕ' of soil? 1 Tri-axial compression test 2 Atterbarg limit test 3 Proctor compaction test 4 Relative density test

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Solution: 2 Concept: Compaction:  👉It is the process in which the soil particles are forced into a denser state by mechanical means, thus decreasing the air voids and hence porosity also reduces. 👉It is an instantaneous phenomenon. 👉Commonly used equipment is a rammer, roller, etc. 🔰Additional Information  📝Consolidation:   👉It is a gradual reduction in the volume of the fully saturated soil due to the dissipation of excess pore water pressure, set up due to an increase in effective stress. 👉It is a time-dependent phenomenon. 🔰Consolidation is believed to occur in three stages:- a) Immediate consolidation:  It occurs if the soil is initially partially saturated and expulsion of air and lateral expansion of soil takes place. b) Primary consolidation:  It occurs due to the expulsion of pore water pressure and depends on the magnitude of stress increase, the compressibility and thickness of the soil layer. c) Secondary consolidation:  It is thought to occur due to the gradual readjustment of clay particles into a more stable configuration following the structural disturbance caused due to decrease in void ratio. It occurs in a very long time #soil

NEXT QUIZ Today at 2 PM TOPIC👇 INDEX PROPERTIES UNIT,CLASSIFICATION OF SOIL be ready👍👍