74 + Interview Questions in Deep Excavations in Construction & Building Materials Page 2 InterviewSolution

51.	Identify the Method used for the dewatering of the foundation trenches.(a) Pumping(b) Freezing process(c) Electro osmosis process(d) Well Point SystemI have been asked this question in an international level competition.My enquiry is from Deep Excavations in section Deep Excavations, Pile Foundations and Caisson of Construction & Building Materials
Answer» Correct answer is (d) WELL Point System Easiest explanation: Well Point System consists of a well POINTS, riser, swinger arm, and header. The area to be DEVOTED is surrounded by NUMBER of well points. The MINIMUM spacing between the well points is 1 m.

Discussion

52.	In case of releasing artesian pressure, which precaution should be taken when the system of well points is adopted.(a) Pumping rate(b) Air locks(c) Duplication of pumps(d) Blowing actionI have been asked this question in homework.My question is based upon Deep Excavations topic in chapter Deep Excavations, Pile Foundations and Caisson of Construction & Building Materials
Answer» Correct answer is (d) BLOWING action To explain I WOULD SAY: Blowing action is adopted for the release of artesian pressure. At some places, the artesian conditions exists at a certain death from the ground LEVEL. If the foundation trench reaches that depth, its bottom is likely to be blown off DUE to hydrostatic pressure.

Discussion

53.	A _______ becomes uneconomical in cases where the plan area of foundation work is small as compared to the depth of water.(a) Cofferdam(b) Caisson(c) Pile(d) PitThis question was posed to me in exam.Query is from Classification of Caissons in division Deep Excavations, Pile Foundations and Caisson of Construction & Building Materials
Answer» The correct choice is (a) Cofferdam Easy explanation: Under such circumstances, cofferdam BECOMES uneconomical. Hence, caisson would prove to be most suitable. At PLACES where cofferdam cannot be Dewatered SUCCESSFULLY, the Caissons are USED.

Discussion

54.	A _____________ is defined as a structure which is sunk through ground or water to exclude water and semi fluid material during the process of excavation of foundations.(a) Cofferdam(b) Caisson(c) Well(d) PitI got this question by my college director while I was bunking the class.My doubt stems from Classification of Caissons in division Deep Excavations, Pile Foundations and Caisson of Construction & Building Materials
Answer» Correct OPTION is (b) Caisson Explanation: A Caisson is a relatively large deep foundation and RESEMBLES is pile foundation in transferring the superstructure load to some DESIRED DEPTH. However, Caisson differs from a pile in SIZE and in the method of construction.

Discussion

55.	The ___________ is based upon the longitudinal wave transmission and end impact.(a) Static formulas(b) Dynamic formulas(c) Empirical formulas(d) Wave action theoryThe question was asked at a job interview.I want to ask this question from Pile Driving Formulas topic in portion Deep Excavations, Pile Foundations and Caisson of Construction & Building Materials
Answer» Correct answer is (d) Wave ACTION THEORY To ELABORATE: The wave action theory is too complex to be used for ordinary cases and it can be applied only after the preparation of CHARTS with the help of electronic COMPUTERS.

Discussion

56.	__________ have been developed for determining the load bearing capacity of piles.(a) Wave action theory(b) Empirical formulas(c) Static formulas(d) Dynamic formulasThe question was posed to me during an online interview.Enquiry is from Pile Driving Formulas in portion Deep Excavations, Pile Foundations and Caisson of Construction & Building Materials
Answer» The CORRECT option is (b) Empirical formulas Best EXPLANATION: Empirical formulas are based on tests that are CARRIED out under limited CONDITIONS and hence such formulas are not generally adopted.

Discussion

57.	Identify the type of pile.(a) Base driven pile(b) Friction pile(c) Swage pile(d) Button bottom pileI got this question during an interview.This intriguing question originated from Different Types of Pile in chapter Deep Excavations, Pile Foundations and Caisson of Construction & Building Materials
Answer» Correct answer is (a) Base DRIVEN PILE To EXPLAIN I would say: Base driven pile consists of a helically welded shell of steel PLATE. A concrete plug is provided at the bottom of the shell and DRIVING its done by allowing pile Hammer to fall on the concrete plug.

Discussion

58.	Identify the type of Well Point System which can suck water up to 5 meters?(a) Single stage system(b) Multi stage system(c) Vacuum system(d) PumpingThe question was posed to me by my school principal while I was bunking the class.I'd like to ask this question from Deep Excavations in chapter Deep Excavations, Pile Foundations and Caisson of Construction & Building Materials
Answer»

Discussion

59.	Identify the type of pile.(a) Swage pile(b) Button bottom pile(c) Simple pile(d) Friction pileI had been asked this question in final exam.My enquiry is from Different Types of Pile topic in division Deep Excavations, Pile Foundations and Caisson of Construction & Building Materials
Answer» Right option is (b) Button bottom pile To EXPLAIN: In Button bottom pile, a CONCRETE button is used at the bottom to provide an enlarged hole in the SOIL when the FILE is being DRIVEN.

Discussion

60.	The _______ method is similar to box sheeting except that the work is carried out in stages and at each stage, and offset is provided.(a) Sheet piling(b) Box sheeting(c) Stay bracing(d) Vertical sheetingThis question was addressed to me in unit test.I'm obligated to ask this question of Deep Excavations topic in portion Deep Excavations, Pile Foundations and Caisson of Construction & Building Materials
Answer» The correct option is (d) VERTICAL sheeting The best explanation: For deep trenches up to about 10 metres in soft ground, the vertical sheeting is adopted. In this for each stage, vertical SHEETS, HORIZONTAL WALES, Struts and BRACES are provided as usual.

Discussion

61.	The __________ is suitable for caisson shoes.(a) Reinforced cement concrete(b) Cast-iron(c) Timber(d) SteelThe question was posed to me by my school principal while I was bunking the class.The doubt is from Classification of Caissons in chapter Deep Excavations, Pile Foundations and Caisson of Construction & Building Materials
Answer» Right choice is (a) Reinforced CEMENT CONCRETE The best explanation: Reinforced cement concrete has more weight and therefore it creates difficulties in handling and floating the Caisson in the early stage of CONSTRUCTION. Therefore it becomes economical to construct a STEEL Caisson with concrete filling.

Discussion

62.	________ type of cofferdam is economical at places where rock is available in plenty.(a) Earth dikes(b) Sand-bags dikes(c) Rock-fill cofferdam(d) Single wall cofferdamI had been asked this question during an internship interview.I need to ask this question from Cofferdam and Caisson in chapter Deep Excavations, Pile Foundations and Caisson of Construction & Building Materials
Answer» Correct OPTION is (c) Rock-fill cofferdam Easiest EXPLANATION: Rock dikes or Rock-fill cofferdams can be used for a depth of water up to about 3 METRES and a suitable even in case of Swift water. The only disadvantage of this type of cofferdam is that it is not IMPERVIOUS.

Discussion

63.	Identify the given pile driving formula.(a) Major Sander formula(b) Merriman formula(c) Ritter formula(d) Kreutzer formulaThis question was posed to me in my homework.My question is based upon Pile Driving Formulas in chapter Deep Excavations, Pile Foundations and Caisson of Construction & Building Materials
Answer» Right option is (d) Kreutzer formula Best explanation: Kreutzer formula can be USED only for Drop hammer and it is GIVEN as above. Where, H1 and H2 = different heights of fall of hammer in centimetre. S1 and S2 = CORRESPONDING Penetration in CM.

Discussion

64.	Identify the type of pile.(a) Simplex pile(b) Franki pile(c) Pedestal pile(d) Pressure pileThis question was posed to me in final exam.The query is from Different Types of Pile in division Deep Excavations, Pile Foundations and Caisson of Construction & Building Materials
Answer» Correct answer is (c) Pedestal PILE To explain I would say: In the Pedestal pile, a concrete pedestal can be seen at the BOTTOM of the pile which is driven into the ground. The pressure is applied on the concrete through the core and at the same time, the CASE is WITHDRAWN and hence the concrete is sprayed into the voids.

Discussion

65.	________ process consists of making a number of holes in the ground and then filling these holes by the cement grout under pressure.(a) Chemical grouting(b) Cement grouting(c) Freezing process(d) Electro osmosis processThe question was asked during an internship interview.The question is from Deep Excavations topic in section Deep Excavations, Pile Foundations and Caisson of Construction & Building Materials
Answer» Correct answer is (b) Cement GROUTING Best EXPLANATION: In cement grouting method, the cement grout, which is a mixture of sand, cement and water is used. The TERM grouting is used to indicate a process of injecting the cementing materials into the CRACKS.

Discussion

66.	Identify the missing data.(a) Jetting hole(b) Header(c) Riser(d) Swinger armI got this question during an interview.The query is from Deep Excavations in section Deep Excavations, Pile Foundations and Caisson of Construction & Building Materials
Answer» CORRECT choice is (b) Header Easiest explanation: A Header is a PIPE to which all the swinger ARMS of the different well points are attached. The header, in turn, is connected to a pumping UNIT. The header is laid on the ground and its diameter varies from 150 mm to 250 mm.

Discussion

67.	Identify the given pile driving formula.(a) Merriman formula(b) Ritter formula(c) Kreutzer formula(d) Dutch formulaI got this question during an interview.The question is from Pile Driving Formulas in division Deep Excavations, Pile Foundations and Caisson of Construction & Building Materials
Answer» Right option is (a) Merriman FORMULA For explanation I would say: Merriman formula is same as the Major Sander formula except that a FACTOR of safety of 6 is used. It is one of the most important pile-driving dynamic FORMULAS.

Discussion

68.	Which the given method is used for dewatering of the foundation trenches.(a) Deep boring(b) Geophysical method(c) Well Point System(d) Analytical methodThe question was posed to me in a job interview.The question is from Deep Excavations in section Deep Excavations, Pile Foundations and Caisson of Construction & Building Materials
Answer» Correct choice is (c) Well POINT System The BEST explanation: A Well Point is a pipe about 1 m long and DIAMETER is about 40 mm to 50 mm. The whole system comprises of a Riser, swinger ARM, header and TOGETHER work as a well point system.

Discussion

69.	The _________ is suitable for caissons of Open Well type.(a) Steel(b) Timber(c) Reinforced cement concrete(d) Cast-ironThe question was posed to me by my school teacher while I was bunking the class.This key question is from Classification of Caissons in division Deep Excavations, Pile Foundations and Caisson of Construction & Building Materials
Answer» RIGHT option is (d) Cast-iron To elaborate: New SEGMENTS of cast iron are BOLTED as the caisson sinks. Cast iron is unsuitable for pneumatic caissons as there is risk of failures due to tension developed by the compressed air. The cost also works out to be more in relation to STEEL or RCC.

Discussion

70.	__________ is useful when depth of water is about 6 metres to 10 meters.(a) Wood or steel sheeting cofferdam(b) Ohio river type cofferdam(c) Rock-filled crib cofferdam(d) Suspended cofferdamI had been asked this question in examination.This interesting question is from Cofferdam and Caisson topic in section Deep Excavations, Pile Foundations and Caisson of Construction & Building Materials
Answer» CORRECT choice is (a) Wood or steel sheeting cofferdam For explanation: For SMALL and ordinary type of cofferdam, the wooden SHEET piles are employed. But when COFFERDAMS are large or where it is not POSSIBLE to drive guide piles due to more depth of water, the steel sheet piles with suitable bracing are used for the construction of this type of cofferdam.

Discussion

71.	__________ it suitable when available working space is limited and the area to be enclosed is small.(a) Single wall cofferdam(b) Double wall cofferdam(c) Dikes(d) Concrete cofferdamThe question was asked during an internship interview.The doubt is from Cofferdam and Caisson in portion Deep Excavations, Pile Foundations and Caisson of Construction & Building Materials
Answer» Correct answer is (a) Single wall COFFERDAM The best I can explain: Single wall COFFERDAMS is suitable up to a maximum depth of water of 25 m. In this type of cofferdam, a single ROW of Piles is used on EITHER side of the cofferdam. The sheet pile maybe of wood or steel. The wooden piles are generally used for depth of water up to about 10 m.

Discussion

72.	In which method a refrigeration plant of required capacity is needed to be installed near the site of work?(a) Pumping(b) Well Point System(c) Freezing process(d) Electro osmosis processI got this question in an interview for internship.I'd like to ask this question from Deep Excavations topic in section Deep Excavations, Pile Foundations and Caisson of Construction & Building Materials
Answer» Right option is (C) Freezing process Best EXPLANATION: The PRINCIPLE of ground freezing process is the USE of refrigeration to convert in-situ pore water to Ice. Hence, refrigeration plant of required capacity is installed near the SITE of work to perform the process of refrigeration.

Discussion

73.	The _______ arrangement of preventing the slip of earth in the foundation trenches is adopted when a large area is to be excavated for depth greater than 10 meters.(a) Sheet piling(b) Runner(c) Box sheeting(d) Stay bracingThe question was posed to me by my school principal while I was bunking the class.My doubt stems from Deep Excavations topic in section Deep Excavations, Pile Foundations and Caisson of Construction & Building Materials
Answer» Correct choice is (a) Sheet piling Explanation: Sheet piling is used when a large AREA is to be excavated for depth greater than 10 meters, soil to be excavated is soft or loose, width of the TRENCH is also large and the SUBSOIL water is PRESENT.

Discussion

74.	The __________ arrangement of preventing the sleep of earth in foundation trenches is used when the excavation is to be carried out in the moderately firm ground.(a) Runner(b) Stay bracing(c) Vertical sheeting(d) Sheet pilingThe question was asked during an interview.My doubt is from Deep Excavations topic in portion Deep Excavations, Pile Foundations and Caisson of Construction & Building Materials
Answer» The correct OPTION is (b) Stay bracing Easiest explanation: In case of moderately firm ground, Stay bracing is adopted when the depth of excavation does not exceed 2 METRES. In this, the vertical sheets of piling boards are PLACED opposite each other against the WALL of the TRENCH.

Discussion

Explore topic-wise InterviewSolutions in .

Identify the type of pile.(a) Base driven pile(b) Friction pile(c) Swage pile(d) Button bottom pileI got this question during an interview.This intriguing question originated from Different Types of Pile in chapter Deep Excavations, Pile Foundations and Caisson of Construction & Building Materials

Identify the type of pile.(a) Swage pile(b) Button bottom pile(c) Simple pile(d) Friction pileI had been asked this question in final exam.My enquiry is from Different Types of Pile topic in division Deep Excavations, Pile Foundations and Caisson of Construction & Building Materials

Identify the type of pile.(a) Simplex pile(b) Franki pile(c) Pedestal pile(d) Pressure pileThis question was posed to me in final exam.The query is from Different Types of Pile in division Deep Excavations, Pile Foundations and Caisson of Construction & Building Materials

Identify the missing data.(a) Jetting hole(b) Header(c) Riser(d) Swinger armI got this question during an interview.The query is from Deep Excavations in section Deep Excavations, Pile Foundations and Caisson of Construction & Building Materials

Identify the given pile driving formula.(a) Merriman formula(b) Ritter formula(c) Kreutzer formula(d) Dutch formulaI got this question during an interview.The question is from Pile Driving Formulas in division Deep Excavations, Pile Foundations and Caisson of Construction & Building Materials