Civil Engineering Notebook (CEN)

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✅ IMPORTANT QUESTION FOR COMING EXAM ❇️National Bank for Agriculture and 💠Rural Development (NABARD): 💠Formation: July 12, 1982 💠Headquarters: Mumbai 💠Chairman: Govinda Rajulu Chintala ❇️Karnataka: 💠Capital: Bengaluru 💠Chief Minister: Basavaraj S Bommai 💠Governor: Thawar Chand Gehlot ❇️Telangana: 💠Capital: Hyderabad 💠Governor: Tamilisai Soundararajan 💠Chief minister: K. Chandrashekar Rao ❇️THDC India Ltd (THDCIL): 💠Founded: 12 July 1988 💠Headquarters: Rishikesh, Uttarakhand 💠Chairman & MD: K. Vishnoi ❇️Sri Lanka: 💠Capital: Jayawardenepura Kotte 💠Currency:Sri Lankan Rupee 💠Prime Minister: Mahinda Rajapaksa 💠President: Gotabaya Rajapaksa ❇️Reserve Bank of India (RBI): 💠Founded: April 1, 1935 💠Headquarters: Mumbai, Maharashtra 💠Governor: Shaktikanta Das Deputy Governors: Mahesh Kumar Jain, Michael Debabrata Patra, M Rajeshwar Rao, T Rabi Sankar ❇️State Bank of India (SBI): 💠Founded: 1 July 1955 💠Headquarters: Mumbai 💠Chairman: Dinesh Kumar Khara SBI MDs: Ashwani Bhatia, C.S. Setty, Swaminathan Janakiraman and Ashwini Kumar Tewari ❇️Staff Selection Commission (SSC): 💠Formation: 4 November 1975 💠Headquarters: New Delhi 💠Ministry: Department of Personnel & Training ❇️IPL 💠Founded: 2008 💠Total Teams: 10 (from 2022) 💠Next edition: 2022 💠Most successful team: Mumbai Indians (5 titles)

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Solution: 3 Concept: CBR (California Bearing Ratio) Method: (IRC 37-1984) The method of design of flexible pavement as recommended by IRC is the CBR method. The CBR method was developed originally by the California State Highway Department. The advantage of the CBR method is that it can be used to find the pavement and that of individual courses in addition thickness of the CBR values of the materials of the courses are also known. The following methods are used for the design of flexible pavements:- 1)Empirical methods 2)Semi-empirical methods 3)Theoretical methods Empirical methods: They are based on the strength properties of the soil subgrade. 1)The Group index method, 2)CBR method and 3)Mcleod method Semi-empirical or Semi theoretical method: These methods are based upon the stress-strain function. 1)Triaxial test method Theoretical Methods: These methods totally depend upon theoretical analysis and mathematical computations. 1)Burmeister method ​ Additional Information Group-Index Method: This method was devised by the U.S. Highway Engineers (Highway Research Board) in1945. The group index of a soil is an arbitrary index assigned to different soil types based on their percentage of fines, liquid limit and plasticity index and is defined by: GI = 0.2a + 0.005ac + 0.01bd where a = (P - 35) < 40 b = (P -15) < 40 c= (WL - 40) < 20 d = (1p - 10) < 20 where P = Percentage fines passing from 0.074 mm sieve. WL = Liquid Limit Ip = Plasticity Index Gmax= 20 and Gmin = 0 Key Points Westergard method is used for rigid pavement. #transportation

Q45)The method of design of flexible pavement as recommended by IRC is: 1 Group index method 2 Westergard method 3 CBR method 4 Benkelman beam method

Solution: 1 Concept: Infiltration: It is the flow of water into the ground through the soil surfaces. Infiltration capacity: It is defined by Horton as the maximum rate at which rain can be absorbed by the soil in the given condition. Horton’s equations: Horton expressed the decay of infiltration capacity with time as an exponential decay ft = fc + (f0 - fc) e^-kt for 0 < t < tc where, ft = Infiltration capacity at any time t from the start of rainfall f0 = Initial infiltration capacity at t = 0 fc = Final infiltration capacity occurring at t = tc k = Horton’s decay constant which depends upon soil characteristic and vegetation cover The main factors that influence the infiltration are as follows: 1. The soil type i.e. texture, structure, hydrodynamic characteristics: The soil characteristics influence capillary forces and adsorption. 2. The soil coverage and vegetation: They increase the time of water penetration in soil. 3. The topography and morphology of slopes: The steep slope has low infiltration capacity as water flow rapidly due to gravity. 4. Rain intensity: High rainfall implies more rate of infiltration. 5. Soil humidity or moisture: Dry soil has more infiltration as compared to wet soil. 6. Soil compaction: High compaction reduces infiltration capacity. 7. Soil thickness: Higher the thickness soil can hold more water. 8. Surface retention or runoff: More surface run-off means less water is available to infiltrate into the soil. 9. Temperature: If the saturated soil temperature is very low, the soil mass becomes impermeable so that the infiltration rate will be below. Hence, The infiltration capacity of the ground does NOT depend on gravity. #hydro

Q40)Infiltration capacity of the ground does NOT depend on 1 Gravity 2 Capillarity 3 Water table 4 Temperature

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Solution: 2 Concept: Water Year: Generally, 1 October to 30 September in the Northern Hemisphere, 1 July to 30 June in the Southern Hemisphere; the annual cycle that is associated with the natural progression of the hydrologic seasons. It commences with the start of the season of soil moisture recharge, includes the season of maximum runoff (or season of maximum groundwater recharge), if any, and concludes with the completion of the season of maximum evapotranspiration (or season of maximum soil moisture utilization). Each country has fixed a definite 12-month period to begin and in a relatively dry season as the water year. In India, the water year starts from June 1st and ends on May 31st of the following calendar year. Important Points: The World Water Day is observed every year on 22nd March to mark the importance of freshwater. #hydro

Q32) Water Year in India starts from the first day of 1 January 2 June 3 April 4 September