For open exploratory workings, justify the method of penetration, the equipment used and, in accordance with the angle of repose of rocks, select and justify the shape and dimensions of the cross section, taking into account the design depth of the working.
For underground mining and exploration workings, justify the method of penetration and the corresponding mining equipment, select and justify the shape and dimensions of the cross section of the working in the clear.
Depending on the physical and mechanical properties of rocks, as well as on the basis of the dimensions of the transport and technological equipment(electric locomotives, trolleys, loading machines), taking into account the clearances provided for by the safety rules (PB) during geological exploration, the dimensions of the cross section are determined mine workings in the light. The dimensions of the workings in the penetration are determined taking into account the thickness of the lining and puffs, as well as the height of the track device (ballast, sleeper, rails).
Mining workings can be carried out with and without fastening. Wood, concrete, reinforced concrete, metal and other materials are used as fastening material. The shape of the section can be: rectangular, trapezoidal, vaulted, round, elliptical.
Horizontal and inclined exploration workings have, as a rule, a short service life, therefore, the main type of lining is wood, the cross-sectional shape is trapezoidal. When driving without fastening, the cross-sectional shape is rectangular-vaulted.
For a trapezoidal cross section of a working with rail transport ( rice. one) it is recommended to calculate the cross-sectional area of the working in the following sequence.
According to the dimensions (width and height) of the electric locomotive or trolley used (with manual haulage), the clear width of a single-track working is determined at the level of the edge of the rolling stock:
B = m + A + n`
and the width of the double-track working:
B = m + 2A + p + n`
m- the size of the gap at the level of the edge of the rolling stock, mm(assumed to be 200 - 250 mm);
p- the gap between the compositions, mm (200mm);
n`- the size of the passage for people at the level of the edge of the rolling stock, mm:
n` = n + *ctg ;
n- the size of the passage at a height of 1800 mm from the level of the ballast layer, equal to at least 700 mm;
h- the height of the electric locomotive (trolley) from the rail head, mm;
h a- the height of the superstructure of the track from the ballast layer to the rail head, equal to 160 mm;
83 0 - the angle of inclination of the racks, taken according to GOST 22940-85 for exploration work.
The height of the working from the rail head to the top rack in the case of the use of contact electric locomotives (before the draft of the support):
h 1 \u003d h kp. + 200 + 100,
h kp.– contact wire suspension height (not less than 1800 mm);
200mm– clearance between the contact wire and the support;
100mm- the value of the possible settlement of the support under the action of rock pressure.
For other modes of transport, the height h1 determined by graphical construction, taking into account the gap C between transport equipment and ventilation pipeline: when transported by battery electric locomotives 250 mm, with manual rollback - 200 mm.
When transporting by battery electric locomotive:
h 1 \u003d h + d t + 250 + 100,
where h- locomotive height, mm;
d t- ventilation duct diameter, mm.
Height h1 in the general case, it should not be less than the height of the loading machine with the bucket raised (for PPN-1s this height is 2250 mm) minus the height of the ballast layer, i.e. h 1 2250 mm.
Clear working width along the ballast layer:
l 2 \u003d B + 2 (h + h a) * ctg ;
Clear working width along the roof:
l 1 \u003d B - 2 (h 1 - h) * ctg ;
The height of the working from the ballast layer to the lining after settlement:
h 2 \u003d h 1 + h a;
Cross-sectional area of the working in the clear after settlement:
S St \u003d 0.5 (l 1 + l 2) * h 2;
The width of the working out in the rough on the roof (when fastening side by side with tightening the sides):
l 3 \u003d l 1 + 2d,
where d- support post diameter (not less than 160 mm).
Width of working out on the soil rough when fastening side by side with tightening of the sides:
l 4 \u003d B + 
,
where h in= 320mm- height from the working soil to the rail head:
h in = h a + h b,
where h b - ballast height.
Working height from soil to support (before draft):
h 3 ` = h 3 + 100,
where . h 3- the height of the working from the soil to the top (after draft).
The height of the working in the rough to the draft in the presence of tightening:
h 4 ` =h 3 ` + d + 50,
where d- diameter of the fastening wood, mm;
50mm- tightening thickness.
Working height after settlement:
h 4 \u003d h 4 ` - 100
The cross-sectional area of the working in the rough before draft:
S 4 \u003d 0.5 (l 3 + l 4) * h 4 `
Vertical draft equal to 100 mm, is allowed only with wooden support.
In the workings, the laying of wooden sleepers and the laying of the track from the rails are used. R24 for trolleys up to 2 m 3. When carrying out exploration workings, trolleys are used VO-0.8; VG-0.7 and VG-1,2 capacity respectively 0.8; 0.7; 1.2 m. When manually rolling with trolleys VO-0.8 and VG-0.7, as well as AK-2u electric locomotives, rails are used R18. The sleepers are laid in a ballast layer with a thickness of 160 mm, immersing them in 2/3 of its thickness.
With a rectangular-vaulted shape, the clear height of the working is the sum of the wall height from the level of the ballast layer and from the height of the arch ( rice. 2).
Rough working height H is defined as the clear height plus the thickness of the lining in the vault with a monolithic concrete lining or plus 50 mm with sprayed concrete, anchor (rod) and combined supports. Wall height from the level of the rail head to the heel of the vault h1 when transported by battery electric locomotives, it is determined depending on the height of the electric locomotive. The height of workings during transportation by contact electric locomotives must satisfy the conditions under which minimum clearances are provided between the electric locomotive (trolley) and the support, as well as between the current collector and the support.
The height of the vertical wall from the level of the tapa to the heel of the vault h 2 = 1800mm. vault height h 0 take depending on the coefficient of rock strength according to the scale of M.M. Protodyakonova.
For monolithic concrete lining with strength coefficient f =3:9, h 0 = B/3.
For sprayed-concrete and anchor lining and in workings without support f 12 ,h 0 \u003d B / 3, and when f 12, h 0 \u003d B / 4.
The curve of the three-center (box) arch is formed by three arcs: axial - R and two side r. The radii of the vault, depending on its height:
| vault height | h 0 | B/3 | B/4 |
| Radius of axial arc | R | 0,692 | 0,905 |
| side arc radius | r | 0,262 | 0,173 |
Design working width B1 for concrete lining it consists of the clear width of the working and twice the thickness of the lining, and for sprayed concrete, anchor and combined lining - from the clear width of the working plus 100 mm.
Single track clearing width:
B=m+A+n
Clear width of a double-track working:
B=m+2A+p+n,
where n= 700mm; p= 200mm.
The height of the vertical wall of the working from the rail head:
h 1 \u003d h 2 - h a \u003d 1800 - 160 \u003d 1640 mm.
Rough working width with sprayed concrete and anchor lining:
B1=B+2 = B + 100,
where = 50mm- the thickness of the support, taken in the calculation.
Cross-sectional area of the working in the clear at the height of the arch h 0 = B/3:
S St. \u003d B (h 2 + 0.26B),
at h 0 = B/4: S sv \u003d B (h 2 + 0.175B),
where h 2 = 1800mm - the height of the vertical wall from the level of the ladder (ballast layer).
Wall height from the working soil:
h 3 \u003d h 2 + h b \u003d h 1 + h B.
Clear output parameter at h 0 \u003d B / 3:
P B = 2h 2 + 2.33B,
at h 0 \u003d B / 4: .P B = 2h 2 +2219B
The cross-sectional area of the working in the rough with sprayed concrete, anchor, combined lining with h 0 \u003d B / 3:
S h. \u003d B 1 (h 3 + 0.26B 1),
at h 0 \u003d B / 4: S h. \u003d B 1 (h 3 + 0.175B 1).
After determining the cross-sectional area, we take according to GOST 22940-85 the nearest standard section and write out its dimensions for further calculations. According to this standard, only the cross-sectional area of the working in the clear is determined, and the cross-sectional area is set in rough depending on the accepted cross-sectional shape, type and thickness of the support according to the above formulas.
Table 1 typical sections and basic equipment used in the calculation of the clear section are given, as well as the dimensions of the basic Vehicle.
The pits are conditionally divided into shallow (up to 5 m), medium (5 - 10) and deep (up to 40 m). The depth of the pits depends on the stage of exploration and geological conditions. Depending on the physical and mechanical properties of the rocks, the method of sinking and the design of the support, the pits are round and rectangular in shape. As the depth of the pit increases, the clear cross-sectional area increases. Holes up to 10 deep m usually have one compartment, and at a depth of up to 20 m may have two compartments. Typical sections ( GOST 41-02-206-81), drilling of pits with a clear cross-sectional area from 0.8 to 4 m 3 and geometric dimensions (Table 2).
The cross-sectional area in the light is the area limited by the internal. By the contour of the support and over the ballast layer of the rail track (excluding the thickness of the support)
Cross-sectional area in the rough - the area along the outer contour of the lining, including the puff and the working soil.
The area limited by its design contour, determined by adding the clearance in the light with the thickness of the support, taking into account the thickness of the tightening and backfilling.
The cross-sectional area of the working in the penetration is the area limited by the contour of the working in the face (it is taken 3-5% more than the area in the rough).
15. Stability of rocks (loose, connected, rocky).
According to the nature of the connection between solid particles, soils are divided into loose, cohesive and rocky.
Loose, non-cohesive soils are characterized by the lack of adhesion between particles, significant water permeability, low compressibility, high internal friction forces and rapid deformation under load.
Cohesive soils are characterized by low water permeability; the presence of water in them determines the molecular cohesive forces. Therefore, cohesive soils are characterized by significant cordon between particles, large deformations under load and duration of deformations.
In rocky soils, their particles are rigidly bonded to each other by a cementing substance, and this bond is not restored if it is broken.
A more complete classification and characteristics of soils are given in reference books and specialized literature.
Soil properties have a significant impact on the nature of their development and the productivity of machines. In this regard, when choosing the type of machine for excavation, it is necessary to take into account the characteristic properties and condition of the developed soils. From this point of view, the most important properties of soils - their resistance to development and their stability as the foundation on which the machine is installed, are determined mainly by the granulometric composition and physical and mechanical properties of the soil.
works, it is necessary to take into account the characteristic properties and condition of the developed soils. From this point of view, the most important properties of soils - their resistance to development and their stability as the foundation on which the machine is installed, are determined mainly by the granulometric composition and physical and mechanical properties of the soil.
The granulometric composition of the soil is characterized by the percentage by weight of particles of various sizes. The size of individual particles of non-rocky soils is: pebbles 40 mm; gravel 2-40 mm; sand 0.25-5 mm; sand dust 0.05-0.25 mm; dusty particles 0.005-0.05 mm and clay particles 0.005 mm.
To assess the most important physical and mechanical properties of the soil, bulk density, loosening, moisture, angle of repose, cohesion (cohesion), fracturing, layering are important.
For horizontal mining and exploration workings, two forms of cross sections are established: trapezoidal (T) and rectangular-vaulted with a duct vault (PS). On fig. 9-10 shows typical sections of mine workings of various shapes.
Distinguish the cross-sectional area of horizontal workings in the light, in the sinking and in the rough. Clear area (S CB) - this is the area enclosed between the support of the working and its soil, minus the cross-sectional area, which is occupied by the ballast layer (if any) poured on the soil of the working.
Area in penetration (5 pr) - the area of development, which it turns out in the process of carrying out before the construction of the lining, rail track laying, the installation of a ballast layer and the laying of engineering communications (cables, air, water pipes, etc.). Area in draft (S BH) - the area of production, which is obtained in the calculation (design area).
Permissible excesses of the area in the penetration over the design one (roughly) are given in Table. 2.
table 2
Rice. 9.1. A typical section of workings of a trapezoidal shape with wooden lining: a - scraper delivery of rock; b - conveyor delivery of rock; c - manual haulage of rock; d - locomotive haulage of rock; e - double-track development with locomotive haulage of rock
Rice. 10. Typical section of workings with monolithic concrete lining with locomotive haulage of rock: a - single-track; b - two-way
Rice. 9.2. Typical section of rectangular-vaulted workings without fastening or with anchor (sprayed-concrete) fastening: a - scraper rock delivery; b - conveyor delivery of rock; c - manual haulage of rock; G - locomotive rock haulage; e - double-track development with a locomotive
rock haulage
Thus, the cross-sectional area of the working in the penetration
or, on the other hand,
Because S B4 = S CB + S Kp, then the calculation of the cross-sectional area of the working begins with the calculation in the light, where S Kp- section of the working, occupied by the lining; K p- cross-section enumeration coefficient (section excess coefficient - KIS).
The dimensions of the cross-sectional area of horizontal workings in the light are determined based on the conditions for the placement of transport equipment and other devices, taking into account the necessary clearances regulated by the Safety Rules.
In this case, it is necessary to consider the following possible cases of workings and calculation of the section:
- 1. The road is secured and the loader is working in the fixed road. In this case, the calculation is carried out according to the largest dimensions of the rolling stock or loading machine.
- 2. The development is carried out with fastening, but the lining lags behind the face by more than 3 m. this case the loading machine works in an unsecured part of the mine.
When calculating the dimensions of the cross-sectional area according to the largest dimensions of the rolling stock, it is necessary to make a verification calculation (Fig. 11):
The interpretation of the data is given below (Table 5).
3. Working out is passed without fastening. Then the dimensions of the section are calculated according to the largest dimensions of the tunneling equipment or rolling stock.
The main dimensions of underground vehicles are standardized in order to typify the sections of workings, the design of the lining and tunneling equipment.
For workings of a trapezoidal shape, standard sections have been developed with the use of solid lining, lining in different directions, with tightening only the roof and with tightening the roof and sides.
Typical sections of rectangular-vaulted workings are provided without support, with anchor, sprayed concrete and combined support.
The main dimensions of typical sections of workings of the T and PS types are given in Table. 3 and 4.
Table 3
The main dimensions of the sections of workings of a trapezoidal shape (T)
|
Designated |
Section dimensions, mm |
Designated |
Section dimensions, mm |
||||||
|
Sectional area in the light, m 2 |
Sectional area in the light, m 2 |
||||||||
Table 4
The main dimensions of the sections of workings of rectangular-vaulted
forms (PS)
|
Designation |
Section dimensions, mm |
Sectional area in the light, m 2 |
||||
Rice. Fig. 11. Schemes of the working conditions of the loading machine in the face: a - in an unsecured bottomhole space; b - in the fixed bottomhole space
Calculation formulas for determining the dimensions of the sections of workings of types T and PS are given in table. 5, 6.
Table 5
Trapezoidal workings
|
Designation |
Calculation formulas |
||
|
Transport equipment |
Selected from catalogs |
||
|
free passage |
|||
|
From soil to head rail |
h =hi + h p + 1/3 /g w |
||
|
Ballast layer (ladder) |
|||
|
Workings from the rail head |
are chosen |
||
|
up to the top |
in accordance with the PB |
||
|
Works in the world: |
|||
|
without rail track |
|||
|
when scraping rock |
|||
|
during conveyor delivery of rock |
h 4 \u003d h + hi |
||
|
in the presence of a rail track: |
|||
|
without ballast layer |
h 4 = h + hi |
||
|
with ballast layer |
h 4 = h+ L3-L2 |
||
|
Rough workings: |
|||
|
without ballast layer |
hs = h4 + d + ti |
||
|
with ballast layer |
hs = h 4 + h + d + ti |
||
|
Transport equipment |
From equipment catalogs |
||
|
Free passage at height h |
Selected in accordance with the PB |
||
|
Passage at the level of transport equipment |
|||
|
In light at the level of transport equipment: |
|||
|
for scraper cleaning |
b = b + 2m |
||
|
single track |
b = b + t + n |
||
|
double track |
b \u003d 2B + c + m-p |
||
|
Workings in the clear on the top: without rail track |
b = b-2(h-H) ctga |
||
|
with a rail track |
B=b- 2(hi - H) ctga |
||
|
Sole: |
|||
|
without rail track |
bi = b + 2H ctga |
||
|
in the presence of a rail track without a ballast layer |
Z>2 = 6 + 2(#+/ji)ctga |
||
|
with ballast layer |
Z>2 = 6 + 2(#+/ji)ctga |
||
|
Designation |
Calculation formulas |
||
|
Rough workings: |
|||
|
upper base |
bz = b+2 (d+ t2) sina |
||
|
bottom base with ballast layer |
ba |
ba = bz +2 hs ctga |
|
|
without ballast layer |
ba = b 2 + 2 (d + t2) sina |
||
|
Between transport equipment |
Selected according to the PB |
||
|
eat and the wall of the workings |
(t> 250 mm With> 200 mm) |
||
|
Between rolling stock |
|||
|
Rack, top made of round timber |
|||
|
Estimated |
|||
|
Distance, mm |
From the axis of the track (conveyor) to the axis of production: single-track |
k = (u + s2 )-S2 |
|
|
double track |
k = s2 -(u+s2 ) |
||
|
Cross section: clear |
R= b+ 62 + 2L4/sin a |
||
|
Pi = bz+ ba + 2/r5/sin a |
|||
|
Cross section: clear |
S CB = /24(61 +b 2 )l2 |
||
|
S m = /25(63 + 6 4)/2 |
|||
Table 6
Rectangular-vaulted workings
|
Designation |
Calculation formulas |
||
|
with sprayed concrete, rod and combined supports |
ho=bl4 |
||
|
with concrete support |
ho = b/2 |
||
|
Works in the world: |
|||
|
without rail track: |
|||
|
when scraping rock |
h 4= h + ho |
||
|
with conveyor |
h 4 \u003d h + /?2 + ho |
||
|
in the presence of a rail track: without ballast layer |
h 4 = h+ /?2 + ho |
||
|
with ballast layer |
h 4= h + ho |
||
|
Developments in draft |
hs= h+ hi + ho +1 |
||
|
Working walls in rough: |
|||
|
when scraping rock |
|||
|
with ballast layer (ladder) |
he = h+ hi |
||
|
Transport equipment |
Selected from catalogs |
||
|
Works in the world: |
|||
|
single track |
b=B+ m+n |
||
|
double track |
b = 2B + c + m + n |
||
|
Developments in draft |
bo = b + 2t |
||
|
Axial arc of the vault: |
|||
|
at ho = N4 |
R = 0.%5b |
||
|
at ho= S 3 |
R= 0,6926 |
||
|
Lateral arch: |
|||
|
at ho = YA |
r= 0,1736 |
||
|
at ho = Yb |
r = 0.262b |
||
|
Perimeter transverse workings, |
|||
|
at ho = YA: without ballast layer |
P = 2he+ 1,219 |
||
|
with ballast layer at ho = b/3: without ballast layer |
P = 2h+ 1,219 P = 2he + 1,33 b |
||
|
with ballast layer |
P = 2h+ 1,33 b |
||
|
Designation |
Calculation formulas |
||
|
Perimeter transverse workings, |
In draft: at ho = N4 at ho = s 3 |
/>1=2*6+1,19*0 />! = 2*6+1,33 bo |
|
|
Cross-sectional area of the mine, m 2 |
|||
|
at ho = YA at ho = S 3 |
S CB = b(h + 0.15b) S CB = b(h + 0.2b) |
||
|
without support or rod support |
SB4= b(h 6 +0,n5b) |
||
|
with sprayed-concrete and combined lining with concrete lining of a rectangular part of the working |
SB4= bo(h 6 +0.15b)S B h = S CB + S+ S 2 +S3 S= 2A 6 /[ |
||
|
vaulted part of the working |
S 2 = 0.157(1 + Ao/6)(6i 2 -6 2) |
||
|
subsoil part of the lining |
S3 |
Si = 2/27/+ hg(t)-t) |
|
|
Dimensions of the subsoil part of the support |
Selected depending on the properties of rocks and width |
||
|
Cutting height |
workings |
||
All horizontal workings along which cargo is transported must have gaps in straight sections between the support or equipment located in the working, pipelines and the most protruding edge of the rolling stock clearance of at least 0.7 m (n > 0.7) (free passage for people), and on the other hand - at least 0.25 m (t > 0.25) with wooden, metal and frame structures of reinforced concrete and concrete lining and 0.2 m - with monolithic concrete, stone and reinforced concrete lining.
The width of the free passage must be maintained at a working height of at least 1.8 m (h = 1,8).
In workings with conveyor delivery, the width of the free passage should be at least 0.7 m; on the other hand - 0.4 m.
The distance from the upper plane of the conveyor belt to the top or roof of the working is at least 0.5 m, and for tension and drive heads - at least 0.6 m.
Gap With between oncoming electric locomotives (trolleys) along the most protruding edge - at least 0.2 m (With> 0.2 m).
In places of coupling-uncoupling of trolleys, the distance from the support or equipment and pipelines located in the workings to the most protruding edge of the rolling stock clearance must be at least 0.7 m on both sides of the working.
When rolling by contact electric locomotives, the height of the contact wire suspension must be at least 1.8 m from the rail head. At landing and loading and unloading sites, at the intersection of workings with workings, where there is a contact wire and along which people move - at least 2 m.
In the near-shaft yard - in places where people move to the landing site - the suspension height is at least 2.2 m, in the other near-shaft workings - at least 2 m from the rail head.
In near-shaft yards, in the main haulage workings, in inclined shafts and slopes, when using trolleys with a capacity of up to 2.2 m 3, R-24 type rails should be used.
Mine rail tracks during locomotive haulage, with the exception of workings with heaving soil and with a service life of less than 2 years, must be laid on crushed stone or gravel ballast from hard rocks with a layer thickness under the sleepers of at least 90 mm.
The cross-sectional shape of a horizontal mining excavation depends mainly on the type of rock support used to protect the excavation from destruction under the pressure of the rocks surrounding it and to maintain the required cross-sectional area for the entire period of exploration. During workings, they are given a trapezoidal or rectangular-vaulted cross-sectional shape. The trapezoidal shape is used for wooden lining and the presence of little pressure from the surrounding rocks. The rectangular-vaulted shape is used for monolithic concrete, sprayed concrete, anchor and combined (anchor with sprayed concrete) lining and in workings that do not have lining (with strong stable rocks).There are cross-sectional areas in the light, in the rough and in the penetration. The clear sectional area is determined by the dimensions of the working to the support, minus the areas occupied by the ballast layer of the rail track and the walkway ladder. The cross-sectional area in the rough is the design area (in penetration). The actual cross-sectional area of the excavation in the penetration is slightly larger than the cross-sectional area of the draft. When driving, it is necessary to observe that the cross-sectional area of the working should comply with the existing "Standards for exceeding the cross-sections of mining workings in driving in comparison with the sections in the rough in the production of geological exploration". Depending on the strength of the rocks, it is allowed to increase the cross-sectional area in the rough by a factor of 1.04-1.12. A large value of the coefficient corresponds to a cross-sectional area of 4 m2 in hard rocks.
The clear cross-sectional size depends on the purpose of the working and is determined by the dimensions of the rolling stock and the number of rail tracks, the width of the conveyor, scraper or loading and transport machine, taking into account the necessary clearances between these machines and the support, which are regulated by safety rules. The gap between the rolling stock and the lining in the long sections of the workings for rail transport is at least 200 mm for monolithic concrete, anchor and sprayed concrete lining and at least 250 mm for other types of lining - pliable metal and wood. If the rolling of trolleys along the working is carried out manually, then for all types of support this gap is 200 mm.