RU1771499C - Method for lowering water level in highland rock burst lake - Google Patents

Abstract

Usage: in construction, engineering geology, hydropower, in particular, when lowering the water level of the flood lakes. SUMMARY OF THE INVENTION: Based on the results of engineering-geological and hydrogeological studies of a dam formed by a landslide from rocks, the location of individual blocks of the landslide body (1), represented by relatively monolithic massifs of rocks, and cracks is established. Cracks are partially formed even before the landslide is displaced during the formation of the bead of the valley as cracks of the side pressure, unloading of compressive stresses and concentration of tensile stresses. These cracks are almost oriented parallel to the buried channel (4). When the landslide is displaced along existing cracks, pro4 VC4 dissects the landslide body into separate blocks, the formation of new secant cracks. During the formation of the dam, the soil is destroyed and collapsed in the side parts with the formation of slopes (5) of the disperse-dispersed soil, which, even more destroyed when it is opened, covers the cavity of the cracks. This is also facilitated by the sedimentation of the silt of the formed lake on the uphill slope. Simultaneously with the identification and mapping of landslide cracks on the surface of the dam, places of water flow on the uphill slope are established both along the edge of the lake water and at non-depths. Then, in the places of the flooded landslide crack outcrops on the uphill slope (6), talus soil and silt are removed, for example, by means of explosions of charges and collapses of soil down the slope. It is also possible to use dredgers. Sequentially clearing the landslides of cracks increases the flow rate of water filtered through the cracks. In this case, the level (7) decreases to the given marks (8). Simultaneously with the development of the soil, the change in the flow rate and flow rate of the water in the downstream is controlled. The development of the soil stops when the flow rate of the water stream and its speed of approach is close to the critical values, i.e. when possible erosion of channel deposits and the transition of the water flow in the village. 2 ill. 8 Yo M XI

Description

The invention relates to construction, engineering geology, hydropower, in particular, to methods for lowering the level of blockage lakes formed as a result of landslide blockages by mountain lands in order to prevent catastrophic floods.

The aim of the invention is to reduce labor costs, the cost of work and prevent catastrophic floods for the dam dam formed by a landslide from rocks, with natural filtration of water along cracks formed by monolithic blocks.

In FIG. 1 shows a schematic section of a dam along a section of a flooded bed of a mountain river; in FIG. 2 is a section AA in FIG. 1.

The method is carried out as follows.

According to the results of engineering-geological and hydrogeological studies of the dam, the location of the blocks of landslide body 1, represented by relatively monolithic massifs of rock, and cracks 2 are established. Cracks 2 partially form even before the landslide is displaced during the formation of the side 3 of the valley as crack cracking, unloading compressive and concentration of tensile stresses. These cracks are practically oriented parallel to the buried channel 4. When the landslide is displaced along existing cracks, the landslide body is cut into separate blocks. The formation of the dam is accompanied by the destruction and collapse of the soil in the side parts of the body, the landslide with the formation of slopes 5 from tidal dispersed soil, which is even more collapsing upon opening, blocks the cavity of cracks and impedes the natural filtration of water along them. This is also facilitated by the sedimentation of the silt of the formed lake on the uphill slope 6. Simultaneously with the identification and mapping of landslide cracks on the surface of the dam, places of water flow on the uphill slope are established both along the edge of the lake water and at the depth. Then, in the places of the flooded landslide crack outcrops on the uphill slope 6, talus and precipitated soil are removed by targeted explosions with a partial collapse of the soil down the slope. Sequentially clearing the landslides of cracks increases the flow rate of water filtered through the cracks. In this case, the level 7 decreases to the set marks 8. Simultaneously with the development of the soil, the change in the flow rate and flow rate of the water in the downstream is monitored. The development of the soil stops when the flow rate of the water stream and its speed of approach is close to the critical values, i.e. when possible

erosion of channel deposits and the transition of a water stream into a catastrophic mudflow, and there will also be a risk of flooding of settlements and destruction of structures located in the valley. If

0 flow rate 9 in the downstream reaches a critical value, then to reduce the influx of water, part of the cavities of the cleared outcrops of cracks can be blocked by the collapse of the soil by explosion of charges 5 from the upper part of the slope, or by covering with a waterproof material.

Example. Sarez Lake in the Pamirs formed as a result of displacement in 1911

0 g landslide with a volume of 2-2.2 km3, blocking the river. Murghab. At present, the maximum depth of the lake is about 500 m. The length of the oval on the uphill slope is 5 m. The average steepness of the uphill slope is about

5 30 °. The volume of water in the lake is about 17 km3. The rate of natural filtration through the dam body is 1.5-4.5 m / s. The body of the blockage consists of huge relatively monolithic landslide massifs

0 from rocky soils (sandstones and slates of the Sarez Formation). The main threat to the existence of the lake level at these elevations is the possibility of displacement commensurate with the landslide blockage, which

5 is being prepared on the starboard side of the lake. In order to prevent a possible catastrophic overflow of water through the blockage, which will cause a landslide displacement, options for lowering the level were developed

0 lakes per 100 m: open with the construction of channels on the surface of the dam and tunnel.

The application of the proposed method can significantly reduce labor costs and the cost of work to reduce the water level in the lake. According to the method of forced collapse of ledges, the specific consumption of B B is 0.03 kg / m. For the collapse of the 10 m layer of a flooded uphill slope to a depth of 100 m within the cracks, in order to clear their exits to the slope, no more than 100 tons of explosives will be required, which, taking into account the costs of transporting the explosives, charging and blasting charges will be worth the cost of the proposed method more than 10 times lower than the cost of existing options.

However, an increase in water filtration through underground channels between massive monolithic blocks will not cause

progressive erosion of the sides of the cracks and, accordingly, the body of the blockage with the formation of a catastrophic flood, since monolithic massifs remain stable and are difficult to erode.

Claims (1)

The claims A method of lowering the water level of a mountain zavalnoe lake, spring-loaded with a dam in the form of a landslide massif of rock, with natural filtration of water along cracks formed by monolithic blocks, including 0 development of the soil of the dam and control of water flow, characterized in that, in order to reduce labor costs, cost of work and to prevent catastrophic floods, the development of the soil of the dam is carried out in the flooded part of the upper slope by means of targeted explosions at the places where the cracks exit to the slope with partial collapse of talus and precipitated soil within the crack, by the collapse of talus and precipitated soil is carried out until the water level in the lake reaches a predetermined level. fifteen  r TrFV / 8 t FIG. 2