A method of evaluating the stability of the pit
The invention relates to the mining industry and can be used in the development of coal, ore and non-ore deposits in an open way, as well as in the construction and maintenance of embankments and dredging roads and Railways. The technical result is to reduce labor costs for measuring and improving the accuracy of prediction of phase formation of the landslide. This method involves identifying areas prone to landslides according to geological sections, periodic measurements of apparent electrical resistivity array in its various points and the definition of the latent stages of development of the landslide on changes over time in the relative values of the measured values. According to geological sections determine the probable location of the sliding surface, the measured apparent resistivity array method elektroregulirovki with its surface parallel to the edge of the ledge above the middle part of the probable slip surface with depth sensing, equal to the depth of the location of the weakened layer, at the level corresponding to the extreme change in resistivity over time in relation to Nacha, and conduct additional measurement method elektroregulirovki, and hidden stages of development of the landslide is judged by the change of the area of the anomalous zone. 2 C.p. f-crystals, 3 ill.
The invention relates to the mining industry and can be used in the development of coal, ore and non-ore deposits in an open way. It can also be used in the construction and maintenance of embankments and dredging roads and Railways.
Known methods of prediction of instability breeds of pit, based on the measurement of deformations or geophysical parameters array associated with changes in stress state.
For example, there is a method of determining a dangerous strain aboard deep career, including the installation of automatic Necronomicon at equal distances in the tunnel, passed at the bottom of the pit across his stretch and cross the area of the sliding surface, and the definition of dangerous deformations in this area (see and. S. No. 1010271, MKI E 21 39/00, publ. 07.04.83, BI No. 13). The method provides a prediction of instability of the pit only in the final stages of a landslide, when the deformation of the array is close to the critical is to, as it involves the driving of a special generation.
Corrective similar to a certain extent contributes to the application of the method of determining changes in stress condition of mine workings, prone to opoznavaniyu, according to which the relevant sections of the measure the main components of the geomagnetic field, find the ratio of the vertical components to the other, and about the change of the stress state of the array and the development of the landslide is judged by the change in this relationship over time (see and. S. No. 1087662, MKI E 21 39/00, publ. 23.04.84, BI No. 15). This method is much less time-consuming, as it requires working driving and even drilling. However, the method does not provide estimates of changes in rock properties in a controlled area, it is not possible to estimate the depth of the location and dimensions of the hearth emerging landslide, indicating that it has insufficient accuracy.
Higher accuracy provides a method for predicting process opolznevaya, including the definition of the zone output unstable horizon on the surface, the separation of the rock prisms, test them on shift with simultaneous measurement of the electrical resistance, the definition of the phase p is and the surface with relation, obtained from testing of prisms (see and.S. No. 1287078, MKI G 01 V 03/06, publ. 30.01.87, BI No. 4). This analogue takes into account the change of physico-mechanical properties of rocks and their stress state, however, its scope is very limited, because when unstable horizon does not go directly on the earth's surface, the method is fundamentally impossible. In real conditions of unstable layers are often located in the depth of the array, where the mechanical and electrical properties of rocks differ significantly.
The most perfect at the moment is a way of assessing the stability of a rock mass of the pit, including the drilling of wells on the site, Prednisolonum to landslides, the choice of the base profile in the zone of equilibrium stress state of rocks, periodic measurements of the apparent specific elektrosoprotivlenie (WES) for base and line profiles from pairwise movement of the feeding electrodes in the wells and the definition of time and space coordinates of the origin of the landslide extreme changes in time relationship of the apparent resistivity of the line profiles to the base, the reduction of this parameter to 0.1-0.5 of the background values associated with the formation of obodan is about ensures high accuracy of estimates of changes in properties and States of rocks in the area of intended landslide and the definition of the latent stages of its development. Accept the described method for the prototype.
The main disadvantage of the prototype is associated with a high complexity of its implementation, because it involves periodic measurements by the method of immersed electrodes across multiple profiles on different levels in depth. In addition, when high detail control the time and place of the origin of the weakened zone, the prototype does not provide sufficient accuracy of prediction of phase formation of the landslide, so, on the area of the weakened zones are judged on only one of its size - the length of the anomalous plot a graph of apparent resistivity along the corresponding line profile.
The objective of the invention is to reduce the complexity of measuring the apparent resistivity of the array in the vicinity of the proposed focus of the landslide due to the use of bestcasinos method elektroregulirovki from the surface to the location of the axis of the main profile parallel to the edge of the ledge above the most likely location of the source of the landslide on the sliding surface, which is determined according to geological data, as well as improving the accuracy of prediction of phase formation of landslide due to measurement additional profile, the axis of which is perpendicular to the axis of the main profile.
This goal is achieved by the fact that in spaspa data, geological sections, periodic measurements of apparent resistivity at various points and the definition of the latent stages of development of the landslide on the changes over time of the measured values, according to the geological sections identify the location of the probable slip surface, measure the apparent resistivity of the array method elektroregulirovki with its surface parallel to the edge of the ledge above the middle part of the probable slip surface with depth sensing, equal to the depth of the location of the weakened layer, at the level corresponding to the extreme change in resistivity over time relative to the initial value measured at steady state species, plan profile, perpendicular to the edge of the ledge, and conduct additional measurement method elektroregulirovki, and about the hidden stages of development of the landslide is judged by the change of the area identified anomalous zones.
This goal is achieved by the fact that the boundaries of the anomalous zone is determined by the location of the points of measurement with a change of apparent resistivity in excess of 20% of the initial value, and its area according to the formulawhere a, b are the dimensions of the zones in the profile.
This goal is achieved by the fact that with the decrease of apparent resistivity in the anomalous zones is Iconium-softening rocks in this area.
The essence of the claimed method is illustrated by drawings.
In Fig.1, 2 shows: geological cross-section comprising layers of rocks 1-5, built according to geological exploration wells 6; identified probable the sliding surface 7; the longitudinal x and transverse y axis elektroregulirovki; the location of the elements of the measuring system AMNB on the surface of the ledge; the location of the detected lesion landslide 8. In Fig.3 shows graphs of the variation of the relative magnitude of the apparent resistivity arrayto/K0at time t1, t2and t3: along the longitudinal axis x along the side of a ledge (a) and in the area of the detected focus of the landslide (b), the transverse axis y (in).
Implement the method as follows.
According to the geological investigations establish the plot, conducive to landslides. This can be a site with a pronounced cleavage, with a layer of loosened rocks, flooded soils, tectonic breaks, as well as a section of the array, composed of loose or unstable silentresident rocks. On the established site to determine the probable location of the sliding surface. In the case of weak layer of surface RMS is about with the plane of the weakened layer. In a homogeneous unstable rocks she has kruglouniversitetskoy form where you can expect special engineering methods. In Fig.2 geological cross-section, uncovered wells 6, contains layers of loamy clay 1 clay 2, m 3, 4 coal, bedrock 5. Likely the sliding surface 7 has the form of a flat surface, coincident with the lower boundary of the flooded clay layer 2.
According to theoretical and experimental studies in the maximum stress state is an array of the ledge in the middle part of the sliding surface (see Arsentiev A. I., Bukin, I. Y., Mironenko Century A. the stability of the sides and drainage pits. M.: Nedra, 1982. - S. 32-33). In this area of the array is most likely the origin of the hearth of the landslide, so the control change the properties of this zone is provided by the claimed method. Spend the vertical from the middle of the sliding surfaces, get started About the longitudinal axis of elektroregulirovki x parallel to the edge of the ledge. On this axis produces measurements of apparent resistivitytoscheme elektroregulirovki from the surface of the ledge install AMNB, and polarizes having electrodes AB/2 is equal to the depth of the location h of the weakened layer that zoo profile Oh hold in the steady state of the array. These measurements it is advisable to before the formation of the ledge. According to the results of periodic measurements at the specified profile build graphs relative values WESto/PK0(x) along the entire length of the ledge (Fig.3A).
Education on the graphto/PK0(x) extremes, in which a changetois greater than 20%, indicates the formation of anomalous zones in the depth of the array, which can become the focus of the landslide. Numerous researchers have established the relationship of resistivity of rocks and soils and their porosity (voidness) and vlagonasyschennyh the formation or the crack opening, softening rocks under deformation resistivity increases approximately in proportion to the ratio of voidness; when filling rocks mineralized fluid decreases inversely proportional to the ratio vlagonasyschennyh voids (see, for example, Dehnow Century. N. Electrical and magnetic methods of exploration. - M.: Nedra, 1981. - S. 10-14). 20% significance test changetoselected from the following considerations. Experience full-scale issledovatelyami is 12-20%. It is caused by the following factors: the status of the surface layer due to seasonal and climatic conditions; inaccuracies installation of electrodes with repeated measurements and instrumentation errors. Variationstomore than 20%, can only be associated with the change of resistivity of the array to an effective depth sensing, that is, education in the controlled area of the array of the anomalous zone, and decreasingtois the water saturation of the array, while increasing its softening. At the level of O1corresponding to the maximum changetoand outline the transverse profile Of1Uperpendicular to the edge of the ledge on which are really measuring the same method with the same depth sensing within the width of the working surface of the ledge. In moments of t2, t3... fix resizing anomalous zones a and b respectively on the chartsto/K0(x) andto/K0(y), the boundaries of the anomalous zone is determined by the location of intersection of the graphs with 20% of the energy it to the required level of detail control in comparison with the previous stage (Fig.3,b, in). The shape of the anomalous zones in the plan, it is reasonable to approximate the ellipse, in this case, its size is calculated by the formula. The increase of S indicates a hidden development focus of the landslide. With increasing S until the critical values increase the probability of transition to an open stage with the deformation and collapse of rocks. To prevent violations of the stability of the pit should take timely measures to strengthen slopes (see, for example, Fisenko, L., Revazov M. A., Galustian E. L. Strengthening of slopes in open pits. - M.: Nedra, 1974. - S. 100-198).
It should be noted that it is known the use of measurements of apparent electrical resistivity methods vertical electrical sounding and profiling for the prediction of flooded areas (see, for example, Momchilov B. C. to Protect the mines from groundwater. - M.: Nedra, 1989. - S. 38-44) or local collapse (see, e.g., Sazonov, C. A., COSIC Doctor of historical Sciences in Geophysics surveying business. - M.: Nedra, 1989. - S. 35-45).
The proposed method also includes the operation, but it is applied in the previously unknown combination with other operations that allows you to specify the modes and parameters of the method elektroregulirovki, in particular the location of the profiles of the ADI anomalous zones.
Stated gives reason to believe that the claimed method meets the criteria of novelty and significance of the differences.
The described method can be used not only in the conduct of mining operations in an open way, but also in the construction of piles of unstable rock and soil, as well as in the construction and maintenance of embankments and dredging roads and Railways, dams and dams of clay soils.
An example of execution. For stability control of the ledge career height of 16 m and a width of 37 m were drilled 3 exploration wells at a distance of 15 m to a depth of 22 meters According to geological core descriptions array Board is composed of the following rocks (Fig.1): loam dense 1; heavy loam and clay dense 2; m 3; 4 coal; Sandstone weak fractured 5. It was found that likely the sliding surface 7 may be adopted by the lower boundary of the wetted layer of clay.
Determining the position of an initial point On, got the depth of the weak layer h=9 m Along the longitudinal axis of Oh measured by the method of elektroregulirovki from the surface of the ledge install A6M6N6B mode feed electrodes AB=2h=18 m autocompensation AE-72 incrementsx=10 m along the entire length of the ledge. Initial grafy blunt. Until t1=6,5 months from the beginning of observations changesto/K0did not exceed 14% (measuring the profile of Oh were held periodically with an interval of 0.5 months). At time t2=7 months at $ x=240 m changeto/K0amounted to 31% (Fig.2A). On a plot of x=200...300 m were repeated measurement incrementsx=2 m (Fig.2B). A point About1corresponding to the minimum value oftoand planned cross profile About1, which carried out additional measurements with stepy=2 m (Fig.2B).
The dimensions and area of anomalous zones were as follows: at time t2=7 months, a2=36,5 m, b2=13.5 m, S2=387 m2; at the time t3=7.5 months and3=68,5 m, b3=24 m, S3=1290 m2. Because fixed reductiontoeducation anomalies associated with the flooding of a clay layer due to the rise of groundwater level in the melting snow. Because hidden process of formation of the landslide intensified, it was decided to stop mining activities and to strengthen the array by setting Stan Sanogo above method reduces the complexity of measuring control space, the time of formation of the source of origin of the landslide and its square, because the measurement is carried out bassclarinet method and profiles with depth sensing, selected in the optimal range on the basis of available geological data. In addition, not giving in detail control, the claimed method provides higher accuracy in comparison with the prototype, because of the stage of development of the landslide is judged not by the source size, and square.
1. A method of evaluating the stability of the rocks of the pit, including the definition of areas prone to landslides according to geological sections, periodic measurements of apparent electrical resistivity array in its various points and the definition of the latent stages of development of the landslide on changes over time in the relative values of the measured values, characterized in that according to geological sections determine the probable location of the sliding surface, the measured apparent resistivity array method elektroregulirovki with its surface parallel to the edge of the ledge above the middle part of the probable slip surface with depth sensing, equal to what chromoprotein in time relative to the initial value, measured at steady state species, plan profile, perpendicular to the edge of the ledge, and conduct additional measurement method elektroregulirovki, and hidden stages of development of the landslide is judged by the change of the area of the anomalous zone.
2. The method according to p. 1, characterized in that the boundaries of the anomalous zone is determined by the location of the points of measurement with a change in resistivity in excess of 20% of the initial value, and its area according to the formula
where a, b are the dimensions of anomalous zones in the profile.
3. The method according to any of paragraphs.1 and 2, characterized in that with the decrease in resistivity in the anomalous zone link formation in the array cracks slip caused by flooding weakened layer, and with the increase in the softening of the rock in this zone.
FIELD: mining industry.
SUBSTANCE: method includes recording signals of electromagnetic radiation in time, measuring amplitudes thereof as well as durations from load start and building spectral-time matrix of spectral amplitude of said signals on basis of results, with growth of frequency and time. On said matrix frequency sub-ranges are marked with growth of frequencies, in each of which equal spectral amplitudes of signals are marked, area taken by these is contoured with closed line and its size is determined, then relation of dimensions of area of Sn n frequency sub-range (n=2, 3, 4,…) to area S1 of first frequency sub-range is determined. With growth of relations of these areas start of intensive crack forming process is detected. Critical relation, at which transfer from intensive cracks forming process to rock massif splitting process occurs, is relation Sn=(2-4)S1, on basis of which splitting of areas on said matrix is predicted in greater frequency sub-ranges, to characterize destruction of rock massif.
EFFECT: higher precision.