Treatment method of open pit slope

The treatment and monitoring of open pit slopes is an important part of mine slope research and daily slope management. It generally includes the treatment of surface water and groundwater, controlled blasting, artificial reinforcement of slopes, and possible and existing slope displacement. The location is monitored for displacement on the ground and in the rock.

(1) Treatment of surface water and groundwater

(1) Construct a drainage ditch outside the slope rock mass to remove surface water and prevent it from flowing into the cracks on the surface of the slope. The existing cracks should be filled in time with appropriate materials.

(2) Drill horizontal drain holes to reduce the water pressure near the cracks or the failure surface.

(3) Drain the well from the periphery of the slope rock mass, assemble a deep well pump or submersible pump for drainage, reduce the water table; and drain the high slope to set two or more drainage levels.

(4) The underground roadway is drained. It can be used for the dewatering of important slope rock mass with complicated hydrogeological conditions. Fan-shaped drainage holes can be used in the roadway to improve the drying effect.

(2) Controlled blasting

(1) Reduce the amount of explosives for each blasting, so that the amplitude of the shock wave is kept as small as possible; the optimum amount of explosive for each blasting should be determined according to the specific mine conditions.

(2) Pre-splitting blasting is the best method widely used at home and abroad to improve the final slope condition of the mine. The method is to drill a row of inclined small-diameter blastholes on the final slope surface, and detonate the holes before the production of the blastholes to form a rupture groove, which reflects the shock wave caused by the production blast and protects the final slope from damage. .

(3) Buffer blasting is to blast a row of holes between the pre-crack blasting zone and the production blasting, the hole spacing is larger than the pre-cracking hole and smaller than the production hole. The detonation sequence is between the pre-split blasting and the production blasting, forming a blasting shock wave absorption zone, further weakening the shock wave transmitted to the slope surface through the pre-cracking blasting zone, so that the slope rock mass remains in an intact state.

(3) Artificial reinforcement of open pit slope

Slope artificial reinforcement is an effective treatment measure for existing landslides and potentially unstable slopes, and it has developed into an important way to improve the design slope angle and reduce the amount of rock fragmentation. Slope reinforcement at home and abroad in the mine, the more extensive use of concrete and shotcrete seepage slope protection measures such as anti-slide pile and metal bolt and anchor, and supplemented.

Anti-slide piles are generally reinforced concrete piles, which can be divided into large section and small section concrete piles. The former is generally used in the slope of soil or soft rock mass to cast concrete in the excavated small well; the latter is generally the rock mass anti-slide pile used in the open pit slope, that is, the steel rail and steel pipe are placed in the borehole. And steel bars as the main anti-sliding structure, then fill the pores in the borehole with concrete or grout with pressure. Anti-slide piles are generally simple to construct, fast, and widely used.

The technology of reinforcement bolts and steel rope anchors for reinforcing slopes has been adopted by many open pit mines and has achieved good results. The anchor rod (cable) generally consists of three parts: the anchor head, the tension section and the anchoring section: the anchor head acts to apply a force to the anchor (cable), and the tension section transmits the tension of the anchor (cable) evenly. For the surrounding rock mass, the anchoring section provides anchoring force. The construction process of the anchor (cable) is more complicated, but it can be used to anchor the slope with a potential slip surface deep. Since a certain prestress can be applied thereto, the stress state of the slope can be actively improved.