A deep trench roadbed excavation construction method

Abstract

The application discloses a deep cutting roadbed excavation construction method, which comprises the following steps: according to the geological state, designing a cutting excavation range and an excavation support scheme, adopting a segmented and layered construction mode, setting a demarcation hole along the longitudinal direction of the cutting, extending and setting a demarcation through section, setting a barrier net in the demarcation through section, connecting the barrier net and the transition rope into an integrated whole through a transition rope, setting a second rope net at the top edge of the adjacent construction section, and temporarily fixing the second rope net on the structure surface of the adjacent construction section through a fixing nail on one side of the second rope net and a transition rope sleeve on the other side, so that a traction protection is formed in the direction of the interface of excavation or blasting, the stability of the boundary and the adjacent construction section is ensured during the excavation construction, meanwhile, the demarcation hole and the demarcation through section can be used as the construction boundary, all the vertical rods, the first rope net, the second rope net and the transition rope can be repeatedly used or used as the components of the subsequent active protection net, and the construction efficiency is improved and the construction cost is reduced.

Description

TECHNICAL FIELD

[0001] The present application relates to the technical field of cutting construction. More particularly, the present application relates to a deep cutting roadbed excavation construction method. BACKGROUND

[0002] Cutting, also known as excavation, is a roadbed excavated from natural strata, which is lower than the natural ground. The cutting with a soil excavation slope height greater than 20 meters or a rock excavation slope greater than 30 meters is called deep cutting. According to different strata materials through the cutting, the cutting can be divided into soil cutting and rock cutting. The height of the cutting slope is determined according to the terrain, geology and hydrology conditions, and the slope should meet the stability requirements. The construction of high slope of cutting is a process of destroying the original mechanical balance of the mountain and re-establishing the mechanical balance of the supporting and reinforcing engineering, and the engineering measures are often implemented after the slope excavation. Before the slope reinforcement and protection measures are implemented, the stress relaxation and strength attenuation of the slope soil will affect the slope stability. In the actual excavation construction process, the geological conditions are complex, and it is not a single earthwork or rock section, so the commonly used single construction scheme cannot be applied. It is very important to design and adjust the excavation and support construction scheme for different geologies to improve the efficiency and ensure the structural safety. SUMMARY

[0003] An object of the present application is to solve at least the above problems and to provide at least the advantages to be described later.

[0004] Another object of the present application is to provide a deep cutting roadbed excavation construction method to solve the technical problem of low construction efficiency of the prior art deep cutting.

[0005] In order to achieve these objects and other advantages according to the present application, a deep cutting roadbed excavation construction method is provided, comprising the following steps:

[0006] S1, obtaining the terrain and geological state of the cutting construction, designing the cutting excavation depth and the slope size range, adopting a stepped slope, and grading excavation, wherein the slope grading height is 10 m, and the platform width is 2-3 m;

[0007] S2, designing the cutting excavation mode and the slope support mode, dividing the excavation area along the transverse direction and the longitudinal direction, setting multiple excavation slopes, setting multiple excavation layers for each excavation slope, dividing each excavation layer into one middle section, two lateral sections and two slope sections from the middle to both sides, and reducing the width of the middle section from top to bottom on the transverse cross section, and constructing a cutting top water collecting ditch before the cutting excavation;

[0008] S3, excavate from top to bottom, each excavation layer is constructed in order from the middle to the sides, before construction, a row of demarcation holes are drilled along the longitudinal direction of the cutting at the intersection of the middle section and the lateral section, at the intersection of the lateral section and the slope section, a demarcation through section is formed by completely penetrating along the longitudinal direction of the cutting between some adjacent demarcation holes, the demarcation through sections are arranged at intervals, a barrier net is inserted in each demarcation through section, the barrier net comprises a pair of vertical rods, a first rope net is connected between the vertical rods, a transition rope is connected between the top of the adjacent two vertical rods of the adjacent two first rope nets, a second rope net is sleeved on the transition rope and can rotate freely relative to the transition rope, a fixing nail is sleeved on the side of the second rope net away from the transition rope, the fixing nail is used to temporarily set on the structural surface layer of the adjacent unconstructed section to lay the second rope net on the surface of the adjacent unconstructed section, the first rope net, the second rope net and the transition rope are all flexible structures, after excavating a middle section or a lateral section, the barrier net structure in the side range is removed, and a corresponding support structure is arranged on the slope of the corresponding layer after constructing an excavation layer;

[0009] S4, perform slope finishing, reinforcement and drainage construction.

[0010] Preferably, in step S3, the types of the support structure include active protective nets, anchor rod frame beams and anchor cable frame beams, the structures and sizes of the first rope net and the second rope net are the same, and each of the first rope net and the second rope net comprises a flexible rope net in the shape of a rectangle, a sleeve lug is connected at each side or corner of the flexible rope net, the sleeve lug is used to be sleeved on the vertical rod or the fixing nail or the transition rope, the flexible rope net sleeved on the vertical rod forms the first rope net, the flexible rope net sleeved on the transition rope forms the second rope net, and the first rope net and the second rope net are taken down for use as active protective nets after the barrier net structure is removed.

[0011] Preferably, when each excavation layer is excavated, the earthwork is excavated by a mechanical method, the stone work is excavated by a mechanical method, a shallow hole bench controlled blasting method and a deep hole bench controlled blasting method, the slope section of the earthwork is blasted by a smooth blasting method, and according to the distance relationship between the surrounding environment and the blast area, the following parameters must be met in the blasting construction of this section, and the specific parameters are as follows:

[0012] Maximum total charge Q = R 3 (V / K) 3 / a ,

[0013] In the formula, Q is the amount of explosive, the total charge for simultaneous blasting, the maximum segment charge for delay blasting, and the unit is Kg,

[0014] R is the safe allowable distance of blasting vibration, and the unit is meter;

[0015] K, a are the coefficient and attenuation index related to the topography and geological conditions between the blasting point and the calculation protection object, which are selected according to the national standard according to the geological conditions of the control blasting point;

[0016] V is the safe allowable speed of the geological point of the protection object, in centimeters per second;

[0017] When selecting deep-hole bench controlled blasting, the drilling diameter D is 90 mm, and the bench height is 5-10 m. When selecting shallow-hole bench controlled blasting, the drilling diameter D is 40 mm, and the bench height is 1.5-3.5 m.

[0018] Preferably, the deep-hole bench controlled blasting parameter design is as follows:

[0019] (1) The unit consumption of explosives q is 0.35 kg / m 3 During actual construction, 1-2 trial explosions and blasting vibration propagation law tests are performed to finally determine the reasonable specific consumption of explosives. The explosive is rock emulsion explosive, and the cartridge diameter is configured according to the drilling diameter D φ70 mm specification emulsion explosive;

[0020] (2) The bench height H = 5-10 m, and the drilling diameter D is selected as φ90 mm type blast hole;

[0021] (3) The base resistance line W1 or the minimum resistance line W,

[0022] W1= (30-40) D (m)

[0023] The smaller value is taken when the rock is hard, and vice versa;

[0024] (4) The blast hole spacing a = m * W1 = (0.7-1.25) W1 (m),

[0025] In the formula, m is the blast hole density coefficient, which is 0.7-1.25, and m is 0.7-0.9 when the front row of blast holes is selected W1;

[0026] (5) The blast hole row spacing b = (0.70-1.0) a (m) ;

[0027] (6) The blast hole over-drilling depth h = (0.15-0.35) W or h = (8-15) D (m) ;

[0028] (7) The blast hole depth L = H + h (m) ;

[0029] (8) The charging length L1 = Q / qx, and qx is the blast hole charging line density. For φ90 mm blast hole, qx = 6 kg / m;

[0030] (9) The tamping length L2 = L—L1 should satisfy L2≥ (1.0-1.3) W1;

[0031] (10) The hole arrangement method is vertical drilling, planar arrangement in the shape of a plum blossom or rectangle or square;

[0032] (11) The calculation formula of the single-hole charge quantity Q of deep-hole blasting

[0033] Q=qHaW or Q=kqHab (kg) (k value is 1~1.1).

[0034] Preferably, the shallow-hole bench blasting parameter design is as follows:

[0035] (1) The unit consumption q is pre-selected as 0.3 kg / m 3 In actual construction, 1~2 trial blasts and blasting vibration propagation law tests are performed to finally determine the reasonable unit consumption of explosives;

[0036] (2) The minimum resistance line W1 of the base plate

[0037] W1= (30~40)D or W1= (0.4~0.6) (m)

[0038] The small value is taken for hard rock, and vice versa;

[0039] (3) The hole spacing a and the hole row spacing b

[0040] The hole spacing a of hard rock is (0.7~1.2)W (m)

[0041] The hole row spacing b is (0.8~1.0)a (m).

[0042] (4) The hole arrangement method is vertical drilling, planar arrangement in the shape of a plum blossom, and the number of hole rows arranged in each blasting is controlled within 3 rows;

[0043] (5) The calculation formula of the single-hole charge quantity Q of shallow-hole blasting

[0044] Q=qaW1H (kg) or Q=kqabH (kg), k value is 1~1.1, H = 1.5~3.5m, the former formula is applicable to the calculation of the hole charge quantity of the hole with a lateral free surface, and the latter formula is applicable to the calculation of the hole charge quantity of each hole row behind the multiple hole rows.

[0045] Preferably, the smooth-hole blasting parameter design is as follows:

[0046] The hole diameter is selected as D=90mm, and the cartridge diameter is φ=32mm;

[0047] The hole spacing a is (8~14)D=0.72~1.26m, and the trial blast is performed according to a=0.8m for hard rock and a=1.0m for soft rock;

[0048] The linear charge density q' is 300 g / m for medium-thin layer fissure developed medium hard limestone and 400 g / m for thick layer medium hard limestone;

[0049] The axial distribution of charge is 1.5 m linear charge density q' at the bottom of the hole 底 = (2-4) q' = 0.60-1.6 kg / m, 1.2 kg / m is taken, 1-1.5 m linear charge density q' at the top 顶 = (0.5-1.0) q' = 0.15-0.4 kg / m, the middle is calculated as normal charge q'middle = 0.3-0.4 kg / m, the hole plugging section is 1.2 m;

[0050] The decoupling coefficient n = D / φ, the value of n is in the range of 2-5;

[0051] The smooth hole depth L = the main hole vertical depth / sin a, a is the slope angle, when the step height is 10 m, L = 12.7 m;

[0052] The plugging length = (12-20) D (m);

[0053] The delay of the smooth hole from the initiation time of the main hole Δt ≥ 50 ms, 75 ms is taken;

[0054] The single hole charge of the smooth hole Q' is according to the formula Q' = q' × L, kg;

[0055] The hole arrangement mode, the main hole and the buffer hole are both arranged in the form of rectangle;

[0056] The structure and plugging design: the smooth hole adopts radial decoupling charge structure, the explosive is bound on the bamboo sheet and is bound tightly in the detonating cord in the hole, the bamboo sheet leans against the reserved slope side, the hole plugging section is 0.8-1.5 m

[0057] Preferably, the charge structure of the shallow hole step control blasting and the deep hole step control blasting adopts continuous column charge, the smooth blasting adopts air interval charge, the strip explosive and the detonator are loaded into the hole when the shallow hole step control blasting is used, the detonator is loaded at 1 / 3 of the charge column, when the deep hole adopts φ70 mm strip charge, the rammer is used for compaction, and the detonator is loaded at 1 / 3 and 2 / 3 of the charge column respectively.

[0058] The present application at least comprises the following beneficial effects: the deep trench roadbed excavation construction method of the present application designs the trench excavation range and excavation support scheme according to the geological state, adopts the segmented and layered construction mode, sets the demarcation hole along the longitudinal direction of the trench between adjacent construction sections, extends and sets the demarcation through section, sets the barrier net in the demarcation through section, and connects the barrier net and the transition rope into an integrated whole through the transition rope, sets the second rope net at the top edge of the adjacent construction section, and the second rope net is connected with the transition rope on one side and is temporarily fixed on the structural surface of the adjacent construction section through the fixing nail on the other side, so that the traction protection is formed in the direction of the interface of excavation or blasting, the role of stabilizing the boundary and the adjacent construction section is played during the excavation construction, the dust and gravel generated during the excavation are blocked, at the same time, the demarcation hole and the demarcation through section can be used as the construction boundary, based on the drilling effect, the current construction section boundary can be reached faster, all the vertical rods, the first rope net, the second rope net, the transition rope and the like can be reused or used as the components of the subsequent active protection net, the construction efficiency can be significantly improved, and the construction cost can be reduced.

[0059] Other advantages, objects, and features of the present application will be apparent from the following description, and will be understood by those skilled in the art. BRIEF DESCRIPTION OF DRAWINGS

[0060] Figure 1 The arrangement structure diagram of the trench of the present application is excavated in the transverse cross-sectional direction in sequence;

[0061] Figure 2 The side view structure diagram of the barrier net and the second rope net structure arrangement of the present application;

[0062] Figure 3 The top view structure diagram of the barrier net and the second rope net structure arrangement of the present application;

[0063] Description of the drawings: 1, demarcation hole, 2, demarcation through section, 3, vertical rod, 4, first rope net, 5, transition rope, 6, second rope net, 7, sleeve ear, 8, fixing nail. DETAILED DESCRIPTION

[0064] The present application will be further described in detail below with reference to the drawings, so that those skilled in the art can implement the present application according to the description.

[0065] It should be noted that the experimental methods in the following embodiments are conventional methods, and the reagents and materials are commercially available unless otherwise specified. In the description of the present application, the terms "transverse", "longitudinal", "upper", "lower", "front", "rear", "left", "right", "vertical", "horizontal", "top", "bottom", "inner", "outer" and the like indicate the orientation or positional relationship shown in the drawings, which is only for the convenience of describing the present application and simplifying the description, and does not indicate or imply that the device or element referred to must have a particular orientation, be constructed and operated in a particular orientation, and therefore cannot be understood as a limitation of the present application.

[0066] As shown in Figures 1-3 The present application provides a deep trench roadbed excavation construction method, comprising the following steps:

[0067] S1, obtaining the topographic and geological state of the trench construction, designing the trench excavation depth and the slope size range, adopting a stepped slope, and grading excavation, the slope grading height being 10 m, and the platform width being 2-3 m;

[0068] S2, designing the trench excavation mode and the slope support mode, layering and segmenting the excavation area along the transverse direction, setting multiple excavation slopes, setting multiple excavation layers for each excavation slope, and dividing each excavation layer into one middle segment, two lateral segments and two slope segments from the middle to the two sides, the width of the middle segment decreasing from top to bottom on the transverse cross section, and constructing a trench top water interception ditch before the trench excavation;

[0069] S3, layering excavation from top to bottom, and constructing each excavation layer in the order from the middle to the two sides, before construction, drilling a row of partition holes 1 at the junction of the middle segment and the lateral segment and at the junction of the lateral segment and the slope segment along the longitudinal direction of the trench, completely penetrating the partition holes 1 between some adjacent partition holes 1 along the longitudinal direction of the trench to form partition penetration segments 2, the partition penetration segments 2 being spaced apart, a barrier net being inserted into each partition penetration segment 2, the barrier net comprising a pair of vertical rods 3, a first net 4 being connected between the vertical rods 3, a transition rope 5 being connected between the top portions of the adjacent two vertical rods 3 of the adjacent two first nets 4, a second net 6 being sleeved on the transition rope 5, the second net 6 being freely rotatable relative to the transition rope 5, a fixing nail 8 being sleeved on the side of the second net 6 away from the transition rope 5, the fixing nail 8 being used for temporarily punching and fixing the structural surface layer of the adjacent unconstructed segment to lay the second net 6 on the surface of the adjacent unconstructed segment, the first net 4, the second net 6 and the transition rope 5 all being flexible structures, after excavating one middle segment or one lateral segment, removing the barrier net structure in the side range, and setting the corresponding support structure on the slope of the corresponding layer for one excavation layer;

[0070] S4, performing slope finishing, reinforcement and drainage construction.

[0071] In this project, the left side slope of the cutting is divided into K18+985-K19+400 left side cutting high slope, the slope length is 415m, the maximum slope height is 33m, and K19+400-K19+758.564 left side cutting high slope, the slope length is 358.564m, the maximum slope height is 61.4m, and K19+460-K19+820 right side cutting high slope, the slope length is 360m, the maximum slope height is 49.3m.

[0072] The maximum height of the K18+985-K19+400 left side cutting high slope is 33m, which is a forward slope. The slope lithology is mainly limestone with argillaceous dolomite, and the slope rock mass is type III. The left side slope adopts bench type slope, and is excavated in stages. The slope grading height is 10m, and the platform width is 2m. The first and second stage slopes are protected by anchor rod frame beams, and the third stage slope is protected by active net + climbing plant. The first, second and third stage slope ratios are 1:0.75. The underground water of the left side high slope is mainly pore water of quaternary unconsolidated rock, fissure water and karst water of bedrock, and the geological condition is mainly limestone with argillaceous dolomite, which is a forward slope. The L2 fissure and the rock layer surface combination intersection line is inclined outward, but the rock layer surface inclination is gentle, the combination intersection line inclination is gentle, the slope rock mass is stable as a whole, and the slope stability is controlled by the strength of the rock mass itself.

[0073] The maximum height of the K19+400-K19+758.564 left side cutting high slope is 61.4m, which is a forward slope. The slope lithology is mainly limestone with argillaceous dolomite, and the slope rock mass is type IV. The left side slope adopts 1:1-1:4 stepped type slope, the slope grading height is 10m, and the platform width is 2m. The first stage slope is protected by anti-slide pile + shrub and grass, the second and third stage slopes are protected by anchor cable frame beam, and the fourth stage slope adopts 1:4 slope. The first, second and third stage slope ratios are 1:1. The underground water of the left side high slope is mainly pore water of quaternary unconsolidated rock, fissure water and karst water of bedrock, and the geological condition is mainly shale with argillaceous dolomite, which is a forward slope. The shale and argillaceous dolomite rock mass is broken, and the slope is supported by anti-slide pile.

[0074] The maximum height of the K19+460-K19+820 right side cutting high slope is 49.3m, which is a forward slope. The slope lithology is mainly limestone with argillaceous dolomite, and the slope rock mass is type IV. The right side slope adopts 1:2.5 slope, the slope grading height is 15m, and the platform width is 2m. The first, second and third stage slopes are protected by shrub and grass. The underground water of the right side high slope is mainly pore water of quaternary unconsolidated rock, fissure water and karst water of bedrock, and the geological condition is mainly shale with argillaceous dolomite, which is a forward slope. The shale and argillaceous dolomite rock mass is broken, and the slope may slide as a whole along the rock layer after excavation. The slope is treated by cleaning the side along the rock layer.

[0075] The earthwork is excavated by mechanical excavation in sections and layers from top to bottom, and the slope is reserved 30 cm for manual finishing. The stone excavation is performed by controlled blasting and mechanical excavation. In the sections near the house, high-voltage line and other structures, mechanical excavation, shallow hole blasting and deep hole blasting are used according to the distance and blasting direction. Smooth blasting is used near the slope. After the stone blasting, a heavy excavator is used to break the stone to the size of the filler diameter. The earthwork and stone are transported to the designated location by excavator and dump truck. Warning zones should be set before blasting, and steel pipe frames or stone blocking nets should be set at the slope foot during blasting to ensure the safety of surrounding structures.

[0076] When excavating the high slope, the top water interception ditch is constructed first. During the excavation process, the excavation surface is always kept at a drainage slope of not less than 4%, and temporary drainage ditches are set to ensure unobstructed drainage and timely and rapid drainage of water from the construction area. Measurement and review must be performed before excavation to ensure that the slope excavation starting point is accurate and that the slope opening line is smooth.

[0077] After each excavation level, the centerline, elevation and width must be re-measured to determine the next opening line. The slope surface is checked with a 2m ruler at uneven places, and the maximum gap should not exceed 15 cm. During the process, monitoring piles are buried according to the design requirements, and settlement and deformation are monitored strictly according to the frequency.

[0078] The longitudinal direction of the cutting is the length extension direction, which is the same as the front and rear direction. Figure 1 The transverse direction of the cutting is the cross-sectional direction, which is the same as the left and right direction. Figure 1The vertical rods 3 are arranged in the left and right directions, and when the middle section is excavated, drilling is performed near the junction between the middle section and the lateral section in the direction consistent with the extension direction of the junction in the transverse section direction. If stone is encountered during drilling, a position marker is placed, or the vertical rod 3 with the marker is replaced. The boundary holes 1 are generally arranged at intervals, and the split-through sections are arranged at intervals. The two vertical rods 3 are sleeved with the first rope net 4 to form a barrier net. One split-through section is inserted with one barrier net. In the direction of the junction between excavation and blasting, the barrier net is pulled for protection. The two vertical rods 3 of adjacent barrier nets are sleeved with a connecting transition rope 5. The transition rope 5 is generally arranged at the top of the vertical rod 3, so that a flexible rope net is formed in the longitudinal direction. A row of flexible rope nets, i.e., the second rope net 6, is sleeved with the transition rope 5. The second rope net 6 can be connected in series or made with a commonly used length and width according to needs. One end of the second rope net 6 is sleeved on the transition rope 5, and the other end is laid on the edge of the lateral section close to the middle section. The outer end is fixed on the lateral section by the fixing nail 8, which plays a certain fixing role. The boundary holes 1 are arranged at the junction of the construction section to insert the barrier net, which plays a role in stabilizing the boundary and the adjacent construction section during excavation construction. The dust and stones generated during excavation are blocked. At the same time, the arrangement of the boundary holes 1 can be used as a construction boundary, which helps to grasp the boundary and the construction progress. In addition, the vertical rod 3 with the marker can predict the position and state of the stone in advance, so as to avoid damage to the artificial or mechanical equipment. All the vertical rods 3, the rope net, the transition rope 5 and other structures can be reused or used as components of subsequent active protection nets, which is conducive to improving the construction efficiency and reducing the construction cost.

[0079] In another technical solution, as shown in Figures 1-3 In step S3, the type of the support structure includes an active protection net, an anchor rod frame beam, and an anchor cable frame beam. The first rope net 4 and the second rope net 6 have the same structure and size, and each include a flexible rope net in the shape of a rectangle. A sleeve ear 7 is connected to each side or corner of the flexible rope net. The sleeve ear 7 is used to be sleeved on the vertical rod 3, the fixing nail 8, or the transition rope 5. The flexible rope net sleeved on the vertical rod 3 forms the first rope net 4, and the flexible rope net sleeved on the transition rope 5 forms the second rope net 6. After removing the barrier net structure, the first rope net 4 and the second rope net 6 are removed for use in the active protection net.

[0080] By setting the first rope net 4 and the second rope net 6 to have the same size structure and setting the sleeve ear 7, a standardized manufacturing structure is formed, production costs are saved, and the length or width range required can be obtained by connecting in series like a jigsaw puzzle for use in subsequent active protection structures. The installation and disassembly of the support structure, the turnover use cost, and the support efficiency of the corresponding position can be significantly reduced.

[0081] In another technical solution, as shown in Figure 1As shown, when each excavation layer is excavated, the earthwork is excavated by a mechanical excavation method, the stone work is excavated by a mechanical excavation, a shallow hole step controlled blasting and a deep hole step controlled blasting method, the slope section of the earthwork is adopted by a smooth blasting, according to the distance relationship between the surrounding environment and the blast area, the following parameters must be met in this section of blasting construction, and the specific parameters are as follows:

[0082] The maximum simultaneous blasting explosive amount Q=R 3 (V / K) 3 / a ,

[0083] In the formula, Q is the explosive amount, the simultaneous blasting is the total explosive amount, the delay blasting is the maximum one-section explosive amount, the unit is Kg,

[0084] R is the safe allowable distance of blasting vibration, the unit is meter;

[0085] K and a are the coefficients and attenuation indexes related to the topographic and geological conditions between the blasting point and the calculated protection object, which are selected according to the geological conditions of the control blasting point according to the national standard, and the reference values are as shown in Table 1;

[0086] V is the safe allowable speed of the geological point of the protection object, the unit is cm / s, and the reference value is as shown in Table 2;

[0087] When the deep hole step controlled blasting is selected, the drilling diameter D is 90mm, the step height is 5-10m, and when the shallow hole step controlled blasting is selected, the drilling diameter D is 40mm, and the step height is 1.5-3.5m.

[0088] According to the geological conditions of the control blasting point, referring to the relevant data, the launching tower and the aqueduct take K=200, a=1.8, V=1.5cm / s, and the related data is shown in Table 3.

[0089] Table 1 (national standard) K and a values of different rock types in the blast area

[0090]

[0091] Table 2 Safe allowable standard of blasting vibration (V value)

[0092]

[0093] Table 3 Relationship table of the distance between the blast area and the protected object and the single-response controlled explosive amount

[0094]

[0095] In another technical scheme, the parameter design of the deep hole step controlled blasting, the shallow hole step controlled blasting and the smooth blasting is specifically as follows.

[0096] The parameter design of the deep hole step controlled blasting is as follows:

[0097] (1) Unit consumption qpre 0.35 kg / m 3 In actual construction, 1-2 trial explosions and blasting vibration propagation law tests are performed to finally determine the reasonable explosive unit consumption. The explosive is rock emulsion explosive, and the cartridge diameter is configured according to the borehole diameter D to configure φ70 mm specification emulsion explosive;

[0098] (2) Step height H = 5-10 m, and a φ90 mm type blast hole is selected for drilling diameter D;

[0099] (3) Chassis resistance line W1 or minimum resistance line W,

[0100] W1 = (30-40) D (m)

[0101] The smaller value is taken when the rock is hard, and vice versa. In this project, W1 = 2.7 m;

[0102] (4) Blast hole spacing a = m * W1 = (0.7-1.25) W1 (m),

[0103] In the formula, m is the blast hole density coefficient, which is 0.7-1.25, and m is 0.7-0.9 when the front row of blast holes is selected W1;

[0104] (5) Blast hole row spacing b = (0.70-1.0) a (m) ;

[0105] (6) Blast hole over-drilling depth h = (0.15-0.35) W or h = (8-15) D (m) ;

[0106] (7) Blast hole depth L = H + h (m) ;

[0107] (8) Charge length L1 = Q / qx, qx is the blast hole charge line density, and qx = 6 kg / m for φ90 mm blast hole;

[0108] (9) Stuffed length L2 = L—L1 should satisfy L2≥(1.0-1.3) W1;

[0109] (10) Hole arrangement method The holes are arranged vertically, and the plane is arranged in a plum blossom shape or a rectangular or square shape. In construction, appropriate adjustments can be made according to the actual terrain changes;

[0110] (11) Calculation formula of single-hole charge quantity Q of deep hole blasting

[0111] Q = qHaW or Q = kqHab (kg) (k value is 1-1.1).

[0112] The blasting parameters of one embodiment data are as shown in Table 4 Deep hole step control blasting parameter table.

[0113] Table 4 Deep hole bench step control blasting parameter table

[0114]

[0115] The shallow hole bench step control blasting parameter design is as follows:

[0116] (1) Unit consumption q pre-take 0.3 kg / m 3 , in actual construction, 1-2 times of trial blasting and blasting vibration propagation law test are carried out, and finally the reasonable explosive unit consumption is determined;

[0117] (2) The minimum resistance line of the chassis W1

[0118] W1= (30-40) D or W1= (0.4-0.6) (m)

[0119] Small value when rock is hard, otherwise take large value;

[0120] (3) Blast hole spacing a and blast hole row spacing b

[0121] Hard rock blast hole spacing a = (0.7-1.2) W (m)

[0122] Blast hole row spacing b = (0.8-1.0) a (m);

[0123] (4) The hole arrangement is vertical drilling, and the plane is arranged in the shape of a plum blossom, and the number of hole arrangement rows is controlled within 3 rows each time;

[0124] (5) The calculation formula of the shallow hole blasting single hole charge quantity Q

[0125] Q=qaW1H (kg) or Q=kqabH (kg), k value is taken as 1-1.1, H = 1.5-3.5 m, the former formula is suitable for the calculation of the hole charge quantity of the lateral free face, and the latter formula is suitable for the calculation of the hole charge quantity of the rear hole of each row. The blasting parameters of one embodiment data are as follows: Table 5 Shallow hole bench step control blasting parameter table.

[0126] Table 5 Shallow hole bench step control blasting parameter table

[0127]

[0128] The smooth hole blasting parameter design is as follows:

[0129] The blast hole diameter is selected as D=90mm, and the cartridge diameter is φ=32mm;

[0130] Hole spacing a = (8-14) D = 0.72-1.26m, a = 0.8m for hard rock and a = 1.0m for soft rock are taken for trial blasting;

[0131] The linear charge density q' is 300 g / m for the medium hard limestone with developed medium and thin layer fissures, and 400 g / m for the thick layer medium hard limestone;

[0132] The axial distribution of charge is that the linear charge density q' is 1.5 m at the bottom of hole 底 = (2-4) q' = 0.60-1.6 kg / m, 1.2 kg / m is taken, the linear charge density q' is 1-1.5 m at the top 顶 = (0.5-1.0) q' = 0.15-0.4 kg / m, the middle is calculated as normal charge q'middle = 0.3-0.4 kg / m, the hole plugging section is 1.2 m;

[0133] The decoupling coefficient n = D / φ, the value of n is in the range of 2-5;

[0134] The smooth hole depth L = the vertical depth of main hole / sin a, a is the slope angle, when the step height is 10 m, L = 12.7 m;

[0135] The plugging length = (12-20) D (m);

[0136] The delay of smooth hole to the initiation time of main hole Δt ≥ 50 ms, 75 ms is taken;

[0137] The single hole charge of smooth hole Q' is according to the formula Q' = q' × L, kg;

[0138] The hole arrangement mode, the main blast hole and the buffer hole are arranged in the form of rectangle;

[0139] The structure and plugging design: the smooth hole adopts radial decoupling charge structure, the explosive is bound on the bamboo sheet, and is bound tightly in the detonating cord in the hole, the bamboo sheet leans to the reserved slope side, and the hole plugging section is 0.8-1.5 m. The blasting parameters of one embodiment data are as shown in Table 6.

[0140] Table 6 Table of smooth blasting parameters

[0141]

[0142] In another technical solution, the charge structure of the shallow hole step control blasting and the deep hole step control blasting adopts continuous column charge, the smooth blasting adopts air interval charge, the strip explosive and detonator are loaded into the hole when the shallow hole step control blasting is used, the detonator is loaded at 1 / 3 of the explosive column, when the hole is deep and the length of charge in the hole is long, the multi-shot detonator initiation mode is used, the detonator is loaded at 1 / 3 and 2 / 3 of the explosive column respectively.

[0143] When the environmental conditions of the blast hole location are complex, for example, the maximum segment charge designed in a continuous charging manner cannot meet the vibration safety requirements, and the blast hole location encounters special geological conditions such as cavities, clay layers, etc., an interval plug section is set. The blast hole plugging requires that the blast hole must be fully plugged except for the charging section to ensure the plugging quality. According to the "Blasting Safety Regulations", the plugging length of each blast hole should be not less than 1.2 times the average value of the bottom resistance line and the charging top resistance line in complex environment blasting. Therefore, the blast hole plugging length of the designed deep hole blasting is not less than 1.2W1 or not less than 30 times the hole diameter. The plugging must be carefully and strictly plugged to ensure the plugging quality. The deep hole control blasting plugging uses drill cuttings backfilling, which is tamped with bamboo rods. The one-hole-one-response initiation mode is used by the middle-to-two-side millisecond section initiation using electronic digital detonator, and the interval time difference of the section delay is set as 25ms between holes and 70ms between rows. When networking, the line card of the digital electronic detonator is all clamped on the connection bus, and the delay time difference should be adjusted and designed according to the blasting vibration measurement.

[0144] Blasting safety distance calculation:

[0145] (1) Individual flying stone safety distance calculation

[0146] According to the empirical calculation formula of deep hole blasting individual flying object: Rf=20Kfn2W (m);

[0147] Where Rf is the open pit blasting flying stone safety distance, m;

[0148] Kf is the safety factor, taken as 1.5;

[0149] n is the blasting action index, taken as 0.75;

[0150] W is the minimum resistance line of the first row of blast holes, m;

[0151] Through calculation, the maximum individual flying stone safety distance of the project blasting is estimated as:

[0152] R=20×1.5×0.752×3.0=51m.

[0153] From the site, the estimated deep hole blasting flying stone distance of the blasting area does not exceed the safety distance of the surrounding protected objects. According to the calculation of the above formula and in accordance with the provisions of the "Blasting Safety Regulations", the safety warning radius for personnel during blasting should be not less than 200m, and when the road needs to be temporarily closed during blasting, the warning post distance of the pedestrians should be greater than 500m from the blasting point.

[0154] (2) Blasting vibration safety distance calculation

[0155] The blasting vibration safety distance calculation of this design uses the formula: R= (K / V) 1 / α *Q1 / 3 (m),

[0156] In the formula, R is the safe distance of blasting earthquake, m; in the design, the distance from the boundary line of each blasting partition to the nearest protected object is taken as the distance;

[0157] Q is the maximum total explosive quantity of a segment of millisecond blasting, and in the design, the maximum explosive quantity of a segment is not more than 77 kg;

[0158] V is the safe speed of blasting earthquake, the surrounding protected objects are various, and the anti-seismic capacity is various; in the design, 1.0 cm / s is taken for ordinary houses, and 2.0 cm / s or less is taken for communication towers for vibration safety checking.

[0159] K and a are the correlation coefficient and attenuation index of blasting medium, K is taken as 200 and a is taken as 1.8 according to the site investigation and the experience of similar projects; when the quality of the building is poor, K is taken as 200 and a is taken as 1.8. The results of checking the safe distance of blasting vibration are shown in Table 7.

[0160] Table 7 Results of checking the safe distance of blasting vibration

[0161]

[0162] According to the above table, the vibration safety range caused by the maximum segment explosive quantity of each region according to the design control is less than the actual minimum distance from the blasting area to each protected object, so the blasting parameters of the design are reasonable.

[0163] Although the embodiments of the present application have been disclosed as above, it is not limited to the application listed in the specification and the embodiments, and it can be fully applied to various fields suitable for the present application, and other modifications can be easily realized by those skilled in the art, and therefore the present application is not limited to specific details and the figures shown and described herein, and the present application is not limited to the general concept defined by the claims and the equivalent range.

Claims

1. A method for excavating and constructing a deep roadbed, characterized in that, Includes the following steps: S1. Obtain the topographic and geological conditions of the road cut construction, design the excavation depth and slope size range of the road cut, adopt a stepped slope, excavate in stages, with a slope stage height of 10m and a platform width of 2-3m; S2. Design the road cut excavation method and slope support method. Divide the excavation area into horizontal layers and vertical segments, and set up multi-level excavation slopes. Each level of excavation slope is set with multiple excavation layers. Each excavation layer is divided into one middle section, two lateral sections and two slope sections from the middle to both sides. In the horizontal section, the width of the middle section decreases from top to bottom. Before the road cut is excavated, the top intercepting ditch is constructed first. S3. Excavate in layers from top to bottom. Each excavation layer is constructed in the order from the middle to both sides. Before construction, at the junction of the middle section and the lateral section, and at the junction of the lateral section and the slope section, a row of dividing holes is drilled at intervals along the longitudinal direction of the cut. Some adjacent dividing holes are completely connected along the longitudinal direction of the cut to form a dividing section. The dividing sections are set at intervals. A barrier net is inserted in each dividing section. The barrier net includes a pair of vertical poles. A first rope net is connected between the vertical poles. Between the tops of two adjacent vertical poles of two adjacent first rope nets A transition rope is connected, and a second rope net is attached to the transition rope. The second rope net can rotate freely relative to the transition rope. A fixing nail is attached to the side of the second rope net away from the transition rope. The fixing nail is used to temporarily fix the second rope net to the surface of the adjacent unconstructed section so that the second rope net can be laid flat on the surface of the adjacent unconstructed section. The first rope net, the second rope net, and the transition rope are all flexible structures. After excavating a middle section or a lateral section, the barrier structure in the lateral range is removed. A corresponding support structure is set on the slope of the corresponding excavation layer. S4. Carry out slope repair, reinforcement and drainage construction.

2. The deep roadbed excavation construction method as described in claim 1, characterized in that, In step S3, the support structure includes active protection nets, anchor bolt frame beams, and anchor cable frame beams. The first rope net and the second rope net have the same structure and size, each including a rectangular flexible rope net. Each side or apex of the flexible rope net is connected to a lug. The lug is used to fit onto the vertical rod, the fixing nail, or the transition rope. The flexible rope net fitted onto the vertical rod forms the first rope net, and the flexible rope net fitted onto the transition rope forms the second rope net. After removing the barrier structure, the first rope net and the second rope net are removed and used for active protection nets.

3. The deep roadbed excavation construction method as described in claim 2, characterized in that, When excavating each layer, mechanical excavation is used for earthwork, and mechanical excavation, shallow-hole bench controlled blasting, and deep-hole bench controlled blasting are used for rockwork. Smooth blasting is used for the slope section of earthwork. Based on the distance relationship between the surrounding environment and the blasting area, the blasting construction in this section must meet the following parameters, as follows: Maximum simultaneous dose Q=R 3 (V / K) 3 / a , In the formula, Q represents the amount of explosive, simultaneous detonation represents the total amount of explosive, and delayed detonation represents the maximum amount of explosive in a single stage, all in kg. R represents the permissible safe distance for blasting vibration, in meters; K and a are coefficients and attenuation indices related to the topography and geological conditions between the blasting point and the target to be protected. They are selected according to national standards based on the geological conditions of the blasting point. V represents the permissible velocity of mass point vibration at the location of the protected object, expressed in centimeters per second. When deep-hole bench controlled blasting is selected, the borehole diameter D is 90mm and the bench height is 5-10m. When shallow-hole bench controlled blasting is selected, the borehole diameter D is 40mm and the bench height is 1.5-3.5m.

4. The deep roadbed excavation construction method as described in claim 3, characterized in that, The deep-hole bench controlled blasting parameters are designed as follows: (1) The unit drug consumption q is pre-set to be 0.35 kg / m 3 During actual construction, 1 to 2 test blasts and blasting vibration propagation law tests were conducted to finally determine the reasonable explosive consumption. Rock emulsion explosives were selected, and the explosive cartridge diameter was configured with φ70mm emulsion explosives according to the borehole diameter D. (2) The step height H = 5 ~ 10 m, and a blast hole with a drilling diameter D of φ90 mm is selected for implementation; (3) Chassis resistance line W1 or minimum resistance line W, in meters. W1 = (30~40)D Take a smaller value when the rock is hard, and a larger value when the rock is soft. (4) Hole spacing a = m * W1 = (0.7~1.25) W1, In the formula, m is the borehole density coefficient, which is taken as 0.7 to 1.

25. When W1 is selected for the front row of boreholes, m is taken as 0.7 to 0.

9. (5) Hole spacing b = (0.70~1.0)a; (6) Over-drilling depth of blast hole h = (0.15~0.35)W or h = (8~15)D; (7) Hole depth L = H + h (m); (8) Charge length L1 = Q / qx, where qx ​​is the linear density of the charge in the borehole. For a φ90mm borehole, qx = 6 kg / m; (9) The filling length L2 = L - L1 should satisfy L2 ≥ (1.0 - 1.3)W1; (10) Hole arrangement: Holes are drilled vertically and arranged in a quincunx, rectangular, or square pattern on the plane; (11) Formula for calculating the charge Q per hole in deep-hole blasting Q = qHaW or Q = kqHab (kg), where k is between 1 and 1.

1.

5. The deep roadbed excavation construction method as described in claim 3, characterized in that, The shallow-hole step controlled blasting parameters are designed as follows: (1) The unit drug consumption q is pre-set to be 0.3 kg / m 3 During actual construction, 1 to 2 test explosions and tests on the propagation law of blasting vibrations are conducted to finally determine the reasonable unit consumption of explosives. (2) Chassis minimum resistance line W1 W1 = (30~40)*D or W1 = 0.4~0.6 m Take a smaller value when the rock is hard, and a larger value when the rock is soft. (3) Hole spacing a and hole row spacing b The spacing between boreholes in hard rock is a = (0.7~1.2)W; The borehole spacing b = (0.8~1.0)a; (4) The hole layout method is to drill vertically and arrange the holes in a quincunx pattern in the plane. The number of holes in each blasting operation is controlled to be within 3 rows. (5) Formula for calculating the charge Q per hole in shallow hole blasting Q = qaW1H (kg) or Q = kqabH (kg), where k is 1~1.1 and H is 1.5~3.5m. The former formula is applicable to the calculation of the charge of boreholes with lateral free faces, while the latter formula is applicable to the calculation of the charge of boreholes in each row behind multiple rows of boreholes.

6. The deep roadbed excavation construction method as described in claim 3, characterized in that, The parameters for the blasting of a smooth surface are designed as follows: The borehole diameter is selected as D=90mm, and the charge cartridge diameter is φ=32mm; Hole spacing a = (8~14)D = 0.72~1.26 m, with a = 0.8 m for hard rock and a = 1.0 m for softer rock for test blasting; For linear charge density q′, take q′=300g / m for medium and thin layers of medium-hard limestone with well-developed fractures, and take q′=400g / m for thick layers of medium-hard limestone; Axial distribution of charge: Linear charge density q′ at 1.5 m from the bottom of the hole 底 =(2 - 4)q′ = 0.60 - 1.6 kg / m, take 1.2 kg / m, linear charge density q′ at the top 1 - 1.5 m 顶 =(0.5 - 1.0)q′l = 0.15 - 0.4 kg / m, the middle is charged normally according to the calculation q′mid = 0.3 - 0.4 kg / m, the hole mouth plugging section l = 1.2 m; The decoupling coefficient n = D / φ, and the value of n is in the range of 2 to 5; The hole depth L of the smooth hole = the vertical depth of the main hole / sinɑ, where ɑ is the slope angle of the side slope. When the step height is 10m, L = 12.7m. Blockage length = (12~20)D; For smooth-surface delayed main blast hole initiation time Δt ≥ 50ms, take 75ms; Single-hole charge amount Q′ for smooth holes: according to the formula Q′=q′×L, kg; The hole layout method is as follows: both the main gun hole and the buffer hole adopt a rectangular hole layout. Structure and plugging design: The open hole adopts a radially decoupled charge structure, the explosive is tied to the bamboo strip, and the detonating cord inside the hole is tied tightly. The bamboo strip is close to the side of the retained slope, and the plugging section of the hole is 0.8-1.5m.

7. The deep roadbed excavation construction method as described in claim 3, characterized in that, The charging structure for both shallow-hole bench controlled blasting and deep-hole bench controlled blasting adopts continuous column charging, while smooth blasting adopts air-gap charging. When using shallow-hole bench controlled blasting, strip explosives and detonators are loaded into the hole, with the detonators installed at 1 / 3 of the explosive charge. When using φ70mm strip explosive cartridges in deep holes, they are compacted with a ram, and the detonators are installed at 1 / 3 and 2 / 3 of the explosive charge, respectively.

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