Question: A caving operation is conducted in a relatively weak rock mass where the joint persistence is 88%. Laboratory testing of intact core shows that Co

A caving operation is conducted in a relatively weak rock mass where the joint persistence is 88%. Laboratory testing of intact core shows that Co = 12,750 psi, and φ = 29◦. Specific weight of rock is 157 pcf. Joint cohesion is 75 psi and joint friction angle is 20◦. Depth of the undercut is 3,750 ft. Development drifts are 13 ft wide by 18 ft high. Loading is expected to increase 100% after caving has reached the surface. If the rock mass is not self-supporting with a safety factor of 1.5, then steel sets will be used, possibly in conjunction with rock bolts and shotcrete. In this regard, spot bolting with 6 ft, 3/4 in. diameter, high strength bolts is standard procedure in any case. Determine a combination support system that will provide a safety factor of 1.5 in any steel support and other reinforcement.

Step by Step Solution

★★★★★

3.42 Rating (155 Votes )

There are 3 Steps involved in it

1 Expert Approved Answer

Step: 1 Unlock

convert units for 17 Given Caving operation joint persistence088 29 Rock Co 12750 psi y ... View full answer

Question Has Been Solved by an Expert!

Get step-by-step solutions from verified subject matter experts

Step: 2 Unlock

Step: 3 Unlock

Document Format (1 attachment)

26-E-G-R (325).docx

120 KBs Word File

Students Have Also Explored These Related Geological Engineering Questions!

A steel plate contains 20 bolts. Assume that 5 bolts are not torqued to the proper limit. Four bolts are selected at random, without replacement, to be checked for torque. (a) What is the probability...

A soil sample 6 in. in diameter and 1 ft long is placed in a fading head permeameter. The falling- head tube diameter is 1 in. and the initial head is 6 in. The head falls 1 in. over a 2-hr period....

A thin steel beam AB used in conjunction with an electromagnet in a high-energy physics experiment is securely bolted to rigid supports (see figure). A magnetic field produced by coils C results in a...

A caving operation is conducted in a relatively weak rock mass where the joint persistence is 88%. Laboratory testing of intact core shows that Co = 12,750 psi, and = 29. Specific weight of rock is...

A caving operation is conducted in a relatively weak rock mass where the joint persistence is 88%. Laboratory testing of intact core shows that Co = 87.9 MPa, and = 29. Specific weight of rock is...

Read theSEC 10-K for Ford Motor, Company. (Attached below) Write a 350- to 700-word paper describing the amounts of current and deferred income taxes. Explain the items that affect both these...

Can someone help me answer what the critical factors for Beyond Meat and the other makers of plant-based meat substitutes are? oing into 2020, Beyond Meat, a producer March 31, 2020, the company's...

Hi, I need help solving this question about the case study below. Can anyone help me out? Question: What would you assess as the fundamental strength of the competitive forces that Beyond Meat faces?...

Crecimiento S.A. currently plows back 40 percent of its earnings and earns a return of 20 percent on this investment. The dividend yield on the stock is 4 percent. a. Assuming that Crecimiento can...

Bright Star Inc. (BSI) is a talent-management company that is preparing to go public. Peter, the CEO, recently learned that BSI and its auditor will be required to follow additional rules when it...

Question 1 0 2 pts Having a call provision in the bond contract would have no value unless the issuer believed the yield on its own debt was likely to decline. True False

A firm has a production function of Q = 0.25KL0.5, the rental rate of capital is $100, and the wage rate is $25. In the short run, is fixed at 100 units. a. What is the short-run production...

1. How is GSKs production organized? 2. Is GSKs secondary supply-chain structure global, regional, or local? Why? 3. What is GSKs basic strategy? 4. Why does GSK spread R&D around the world? 5. What...

1. Since HSBC does business with the Peoples Republic of China and has substantial holdings of Chinese yuan (renminbi) on hand, what risk does this pose for the bank? 2. How could HSBC manage its...

Peek Corporation owns 70% of the common stock of Seacrest Company. The stock was purchased for $420,000 on January 1, 2007, when Seacrest Companys retained earnings were $100,000. Preclosing trial...

Fill in the missing data for each of the following independent cases. (Ignore income taxes.) Sales Varlable Total Fixed Net Income Break-Even Sales Revenue $40,000 80,000 Revenue Expenses...

Does still air cause the same At what temperature chill factor as -5C air moving at 15 m/s?

Use Thevenins Theorem to find Vo in the circuit shown Ix vo 2 Ix

Use Thevenins Theorem to Find Io in the circuit shown # 2Vx Io

Find Vo in the network shown using Thevenins Theorem 12V

The probability distribution of DMH returns is as follows: Calculate the standard deviation of the returns. Anne Green holds the following portfolio: What is the portfolio's rate of return?

a. Several years ago, Castles in the Sand Inc. issued bonds at face value of $1,000 at a yield to maturity of 7.4%. Now, with 8 years left until the maturity of the bonds, the company has run into...

What is the NPV of the following set of cash flows (below) at a discount rate of zero percent? NPV= __________ How do you calculate this? What is the NPV if the discount rate is 10 percent? NPV =...