Rock Mechanics And Roof Supporting MCQ
Test your knowledge with important Rock Mechanics And Roof Supporting MCQ and their applications. These MCQs are beneficial for competitive exams too. Explore 30+ more Rock Mechanics And Roof Supporting MCQs on Bissoy. Bissoy App
-
The components of state of stress at a point in x - y plane are given as σ<sub>xx</sub> = 5 MPa, σ<sub>yy</sub> = 10MPA and $${\tau _{xy}}$$ = 2MPa. The sum of the principal stresses acting on the x - y plane in MPa is
-
From a series of tri-axial tests conducted on some sandstone specimens, the relationship between the major and the minor principal stresses in MPa is found to be σ<sub>1</sub> = 100 + 5 σ<sub>3</sub>. The angle of internal friction in degrees of that sandstone is
-
During uniaxial compressive testing of a rock specimen of diameter 54 mm and length 120 mm, the axial strain was found to be 6.5 × 10<sup>-4</sup> mm/mm. If the Poisson's ratio of the rock is 0.3, the volumetric strain of the rock specimen in mm/mm is
-
The objective of such activity is to restrict displacements of the country rock to elastic orders of magnitude and to maintain as far as practicable the integrity of both the country rock and the unmined remnants within the ore body. Identify the mining activity?
-
The measurements of a site investigation are as follows:<br>In = 9, Jr = 1.5, Ja = 2.0, Jw = 1.0. SRF = 2.5. The RQD values taken from five boreholes of the area are 94.2, 95.6, 99.4, 95.3 and 98.0 respectively. The rock mass quality index (Q) is
-
If a rock type has RMR value 70, then what will be its roof class?
-
The specific gravity of gypsum mineral is 2.4. If the density of a gypsum core is 2100 kg/m<sup>3</sup>, the porosity of that core is
-
After every round of blasting, support of roof and sides shall be tested at places within the zone of influence of blasting. Who decides this zone?
-
In a point load test on 50 mm diameter core specimen. rupture was observed at a load of 5000 kg. The uni-axial compressive strength of the specimen was
-
The ratio of uniaxial compressive strength to uniaxial tensile strength of a sandstone specimen is 8 : 1. The theoretical, value of angle of internal friction of the specimen in degree is
-
The uni-axial compressive strength and modulus of elasticity of a rock sample are 90 MPa and 30 GPa respectively. The stored strain energy per unit volume in kN.m/m<sup>3</sup> of the sample at the time of failure is
-
In order to maintain contact with the immediate roof, laggings are put with the cross-bars. The norms of putting such laggings is
-
Support plan of any underground mine shall be approved by
-
It is an electrical resistance thermometer made from a semi-conductor having a large, negative temperature co-efficient useful to measure the rock temperature
-
The pressure on a phreatic surface is
-
Which of the following is not a contributory factor for the cause of the subsidence?
-
"A crack will extend only when the total potential energy of the system of applied forces and material decreases or remain constant with an increase in crack length" - Who has given this concept?
-
A tension crack of 5 m depth behind a rock slope crest is completely filled with water. What is the horizontal force exerted on a unit slope length by the water in the tension crack?
-
A series of tri-axial compression tests conducted on sandstone samples reveal the following relationship between major and minor principal stresses σ<sub>1</sub> = 50 + 30σ<sub>3</sub> [stresses are in MPa)<br>The cohesion in MPa and angle of internal friction in degrees of sandstone respectively are
-
What will be safe cover i.e. the tolerance limit for extraction of coal pillars with caving where railway line is on the surface? T is the seam thickness in meter
-
Which of the following may be called as quick setting support?
-
In freshly exposed roof area of developing working, which of the following support should be preferably used?
-
What do you mean by effective stress?
-
For a typical hard rock with E = 10<sup>5</sup> Mpa and Poisson's ratio $$\left( \upsilon \right)$$ = 0.25, the modulus of rigidity in GPa is
-
Which of the following cell is sometimes used to investigate the shear behaviour of discontinuities?
-
Computational methods of stress analysis fall into two distinct categories - one of them is intregral, what is the other?
-
Which of the following bolting density has been prescribed for poor types of roof?
-
Powered support is used in
-
A rock specimen of 120 mm length and 54 mm diameter is subjected to uniaxial compressive loading. Two strain gauges, one axially and other radially, are attached to the specimen. At the breaking load, if these two gauges read 0.0082 m/m and 0.0023 m/m respectively, the Poisson's ratio of the specimen is
-
The uniaxial compressive strength of a limestone sample is 80 MPa. The sample is confined at a pressure of 20 MPa in a triaxial compressive strength test. Based on Hoek-Brown failure criteria the maximum principal stress at failure in MPa is<br>(Consider rock constants as m = 7.88, s = 1.0 and a = 0.5)