What is Mi in Hoek Brown?
The m i is an important parameter in the use of the Hoek-Brown failure criterion. It can be estimated using a triaxial compressive strength test but in many projects there is no actual test result for the parameter. An estimation of m i comes from a reference table giving a constant value.
What is rock mass strength?
The rock. mass strength criterion is based on a. Mohr-Coulomb model for shear strength in which. the cohesion and friction are those of the rock mass. and determined by classification of the rock mass.
What is the difference between intact rock and rock mass?
The intact rock may be considered as a continuum or polycrystalline solid among discontinuities comprising an aggregate of minerals or grains. The rock mass is the in situ medium comprising intact rock blocks separated by discontinuities such as joints, bedding planes, folds, sheared zones, and faults.
What is the meaning of intact rock?
Intact rock refers to the unfractured blocks between discontinuities in a typical rock mass. These blocks may range from a few millimeters to several meters in size (Hoek, 1994; Hudson and Harrison, 1997).
What is rock mass behavior?
Mining activities change the stress distribution and water conditions in the surrounding rock mass and thus results in a change in behaviour of the rock mass and consequently may result in alteration to its structure. Various manifestations of rock mass behaviour can be identified in all phases of mining activities.
What are the three most common rock mass classifications?
This system forms the foundation for the development of three most common rock mass classification schemes i.e. Q, RMR, and GSI. This conservative method has been modified and improved over time and is still used today to aid in the design of tunnels.
What is RMR and RQD?
RQD is determined from rock cores or volumetric joint count; it is the percentage of rock cores in one meter of drill run. RMR is determined as an algebraic sum of ratings for all of the parameters.
What is the difference between rock mass and intact rock?
What is intact strength?
Intact rock strength (IRS) is a major rock property. Intact rock strength determines the strength of the intact rock block material and as such governs partially the strength of a rock mass. Standard determination of the IRS is by means of a unconfined compressive strength (UCS) test.
What property is a rocks mass?
The properties Em and σcm are the rock mass values of deformation modulus and compressive strength respectively. These designations and parameters are all discussed in detail by Hoek et al. (1995). The terms σ[field], Vp and Vs are the (in-situ) field stresses and P- and S-wave acoustic velocities within the rock mass.
What is difference between rock and rock mass?
Rock material is the term used to describe the intact rock between discontinuities; it might be represented by a hand specimen or piece of drill core examined in the laboratory. The rock mass is the total in-situ medium containing bedding planes, faults, joints, folds and other structural features.
What is Q value in rock?
The Q-value gives a description of the rock mass stability of an underground opening in. jointed rock masses. High Q-values indicates good stability and low values means poor. stability.
What is BMR and RMR?
Basal metabolic rate (BMR) and resting metabolic rate (RMR) both measure the amount of energy —in calories —that your body needs to stay alive and function properly. Many people use the two terms interchangeably, but they have slightly different meanings.
How do you calculate RMR?
Resting Metabolic Rate (RMR) equations:
(RMR) kcal/day: (males) = 9.99 x weight (kg) + 6.25 x height (cm) – 4.92 x age(years) + 5; (RMR) kcal/day: (females) = 9.99 x weight(kg) + 6.25 x height (cm) – 4.92 x age (years) – 161.
What is intact rock block?
What is the 3 types of rocks?
There are three main types of rocks: sedimentary, igneous, and metamorphic. Each of these rocks are formed by physical changes—such as melting, cooling, eroding, compacting, or deforming—that are part of the rock cycle. Sedimentary rocks are formed from pieces of other existing rock or organic material.
What are the 7 properties of rocks?
Most minerals can be characterized and classified by their unique physical properties: hardness, luster, color, streak, specific gravity, cleavage, fracture, and tenacity.
Why do we classify rock mass?
The main benefits of rock mass classifications: Improve the quality of site investigations by calling for the minimum input data as classification parameters. Provide quantitative information for design purposes. Enable better engineering judgement and more effective communication on a project.
What is the difference between RMR and Q-system?
Weakness zones are characterized differently in the three systems. In the RMR, no special parameter is used; the Q applies a classification based on composition and depth of the zone; in the RMi the size of the zone is used.
What is the value of good RQD?
75–90
7.2 Classification Parameters
| Rock Quality | RQD Index in % |
|---|---|
| Poor | 25–50 |
| Fair | 50–75 |
| Good | 75–90 |
| Excellent | 90–100 |
Should I use BMR or RMR for weight loss?
Your BMR is a more accurate way to measure your metabolism at complete rest. It’s usually slightly lower than your RMR. Your RMR is a better number to reference for your daily calorie needs. It more accurately represents the calories you burn in a typical day.
How many calories do I naturally burn a day?
Most people will burn over 1800 calories every day, without doing any exercise at all. As Dr Potter explains, this is because we burn most of our calories just through daily bodily functions. “Our bodies have all sorts of different housekeeping functions they have to maintain even at rest.
How many calories does 10000 steps burn?
What is 10000 Steps Equal To? “But,” continues Jamie, “if you walk briskly for 30 minutes and include enough activity throughout the day to reach the combined total of 10,000 steps, you’re burning about 400 to 500 calories a day, which means you’re losing one pound each week.”
How many calories do I burn laying in bed all day?
As a very approximate number, we burn around 50 calories an hour1 while we sleep. However, every person burns a different amount of calories during sleep, depending on their personal basal metabolic rate2 (BMR).
What does MPa stand for in rock?
Definition of Metamorphism
In geology, however, we restrict diagenetic processes to those which occur at temperatures below 200oC and pressures below about 300 MPa (MPa stands for Mega Pascals), this is equivalent to about 3000 atmospheres of pressure.