What can be done to improve the properties of rock masses?
Certain treatments used to enhance the properties of rock mass are discussed below.
Reinforcement for rocks can be provided in the form of rock bolts, cable anchors, shotcrete, and compaction grouting to improve the rock quality and stability.
- Rock Bolts and Cable Anchors. …
- Compaction Grouting. …
What is rock reinforcement?
Rock reinforcements are additional supports provided to the rock structures to improve its stability and load carrying capacity. Rock reinforcement utilizes the inherent property of the rock structures to behave like a self-supporting single unit.
Why is rock bolting done in rocks?
rock bolt, in tunneling and underground mining, steel rod inserted in a hole drilled into the roof or walls of a rock formation to provide support to the roof or sides of the cavity. Rock bolt reinforcement can be used in any excavation geometry, is simple and quick to apply, and is relatively inexpensive.
What is rock bolting and anchoring?
Anchors and rock bolts (Fig. 4.35) involve the same mechanical principle, but they are employed in soft soil and rock, respectively. Anchors and rock bolts are active reinforcing elements designed to anchor and stabilize the rock mass during tunnel excavations.
What are the factors that affect the strength of rock explain?
The principal factors controlling the strength of solid rocks are: I) mineral composition, structure and texture; 2) bedding, jointing and anisotropy; 3) water content; 4) state of stress in the rock mass.
What are the various methods of determining engineering properties of soil and rock?
The two most common in-situ test methods for use in soil are the Standard Penetration Test, (SPT) and the cone penetrometer test (CPT). Section 5.4 describes these tests as well as other in-situ tests.
How does rock bolting work?
Rock bolts work by ‘knitting’ the rock mass together sufficiently before it can move enough to loosen and fail by unraveling (piece by piece). … Unlike common anchor bolts, rock bolts can become ‘seized’ throughout their length by small shears in the rock mass, so they are not fully dependent on their pull-out strength.
What do you mean by rock reinforcement discuss the various reinforcement mechanisms specifying its suitable conditions?
Rock reinforcement is widely used in tunnels and surface and underground mines. … It provided support to the rock structures to improve its stability and load carrying capacity . Rock reinforcement is used to pre-load the foundation.It can be used to provide a reaction during the pile load test.
How do rock anchors work?
Rock Anchors For Rock Stabilization & … A ground anchor generally consists of a steel tendon (bar or strands) that is grouted into a pre-drilled hole in rock or soil. After the grout cures, the tendon is pulled into tension against a plate or block and is locked in place to resist movement of a retaining structure.
What is the meaning of rock bolting?
[′räk ‚bōlt·iŋ] (engineering) A method of securing or strengthening closely jointed or highly fissured rocks in mine workings, tunnels, or rock abutments by inserting and firmly anchoring rock bolts oriented perpendicular to the rock face or mine opening.
What is rock bolting mechanics theory?
The essential function of bolting is to keep the fractured rock together to form a pressure arch around the opened space. In other words, the bolts help the rock to strengthen and support itself. Rockbolts also provide a holding function to loosened blocks and fractured rock.
What is rock anchoring in geology?
ACIL uses Rock anchors in civil and mining structures to counteract uplift forces acting on foundations and post-tension existing concrete structures. … For most applications the rock anchors are tensioned to a force higher than what is necessary to resist the foundation uplift force.
What are the different types of bolts used for rock bolting?
What are the Types of Rock Bolts?
- Grout-Anchored Rock Bolt. A grouted rock bolt is a threaded bar made of steel, or rebar bolts. …
- Cable Bolts. …
- Hollow Rock Bolts. …
- Self-Drilling Rock Bolt. …
- Mechanically Anchored Rock Bolts. …
- Friction-Anchored Rock Bolts. …
- MDX Bolt. …
- Fiber-Reinforced Polymer Composite Rock Bolts.
What is roof bolting in mines?
A system of roof support in mines. Boreholes usually from 3 to 12 ft (1 to 4 m) long are drilled upward in the roof, and bolts of 5/8 to 1 in (2 to 2.5 cm) or more in diameter are inserted into the holes and anchored at the top by a split cone, mechanical anchor, or resin grout.
What are the types of rock bolts?
The mechanical models were then presented for four types of rockbolts: mechanical rockbolt, fully encapsulated rockbolt, frictional rockbolt, and energy-absorbing rockbolts.