Deep cutting roadbed excavation construction method

Abstract

The invention discloses a deep cutting roadbed excavation construction method, which comprises the following steps of: designing a cutting excavation range and an excavation support scheme according to a geological state, adopting a segmented and layered construction mode, forming a boundary hole between adjacent construction sections along the longitudinal direction of a cutting, arranging a boundary through section in an extending manner, and arranging a blocking net in the boundary through section, second rope nets are arranged on the edges of the tops of the adjacent construction sections, one sides of the second rope nets are connected with the transition ropes in a sleeved mode, the other sides of the second rope nets are temporarily fixed to the structural faces of the adjacent construction sections through fixing nails, and therefore traction protection is formed in the excavation or blasting interface direction. The boundary hole and the boundary through section can be used as a construction boundary, all the vertical rods, the first rope net, the second rope net, the transition rope and other structures can be repeatedly used or used as components of a follow-up active protective net, the construction efficiency can be remarkably improved, and the construction cost can be remarkably reduced.

Description

Technical Field

[0001] The present invention relates to the technical field of road cutting construction, and more specifically, to a deep road cutting roadbed excavation construction method. Background Art

[0002] Cuttings, also known as excavations, are roadbeds made by excavating natural strata that are lower than the natural ground. Cuttings with soil excavation slopes greater than 20 meters or rock excavation slopes greater than 30 meters are called deep cuttings. According to the different stratum materials through which the cuttings pass, they can be divided into soil cuttings and stone cuttings. The height of the cutting slope depends on the topography, geology and hydrology, and the slope should meet the stability requirements. The construction of high slopes of cuttings is a process of destroying the original mechanical balance of the mountain and re-establishing the mechanical balance with support and reinforcement projects, and the engineering measures are often implemented only after the slope is excavated. Before the slope reinforcement and protection measures are implemented, the slope soil will produce stress relaxation and strength attenuation, thus affecting the stability of the slope. In the actual excavation construction process, the geological state is complex, and it is not a single earthwork or stonework section. Therefore, the commonly used single construction plan cannot be applied. It is very important to design and adjust the excavation support construction plan for different geology in a targeted manner to improve efficiency and ensure structural safety. Summary of the invention

[0003] An object of the present invention is to solve at least the above problems and to provide at least the advantages which will be described hereinafter.

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

[0005] In order to achieve these purposes and other advantages according to the present invention, a deep cutting roadbed excavation construction method is provided, comprising the following steps: S1. Obtain the topographic and geological conditions of the road cutting construction, design the road cutting excavation depth and slope size range, adopt a stepped slope, graded excavation, the slope grade height is 10m, and the platform width is 2-3m; S2. Design the road cutting excavation method and slope support method. Divide the excavation area into layers horizontally and sections vertically, set up multiple excavation slopes, and set up multiple excavation layers on each excavation slope. Each excavation layer is divided into a middle section, two lateral sections and two slope sections from the middle to the sides. On the transverse section, the width of the middle section decreases from top to bottom. Before excavating the road cutting, construct a drainage ditch on the top of the cutting first; S3. Excavate in layers from top to bottom. Each excavation layer is constructed in the order from the middle to the two sides. Before construction, a row of boundary holes are drilled at intervals along the longitudinal direction of the road cut at the junction of the middle section and the lateral section and at the junction of the lateral section and the slope section. Some adjacent boundary holes are completely connected along the longitudinal direction of the road cut to form boundary through sections. The boundary through sections are arranged at intervals. A blocking net is inserted in each boundary through section. The blocking net includes a pair of vertical bars. A first rope net is connected between the vertical bars. Between the tops of the two adjacent vertical bars of the two adjacent first rope nets, a first rope net is inserted between the tops of the two adjacent vertical bars of the two adjacent first rope nets. A transition rope is connected, and a second rope net is sleeved on the transition rope. The second rope net 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 fix it on the surface of the structure 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 blocking structure within the side range is removed, and a corresponding support structure is set on the slope of the corresponding layer when constructing an excavation layer; S4. Carry out slope repair, reinforcement and drainage construction.

[0006] Preferably, in step S3, the types of the support structure include active protection nets, anchor frame beams, and anchor cable frame beams. The first rope net and the second rope net have the same structure and size, and each include a rectangular flexible rope net, and a sleeve ear is connected to each side or top corner of the flexible rope net, and the sleeve ear is used to be mounted on the vertical pole or the fixing nail or the transition rope. The flexible rope net mounted on the vertical pole forms the first rope net, and the flexible rope net mounted on the transition rope forms the second rope net. After removing the blocking structure, the first rope net and the second rope net are removed for use as an active protection net.

[0007] Preferably, when excavating each excavation layer, mechanical excavation is used for earthwork, mechanical excavation, shallow hole step controlled blasting and deep hole step controlled blasting are used for stonework, and smooth blasting is used for the slope section of earthwork. According to the distance relationship between the surrounding environment and the blasting area, the blasting construction of this section must meet the following parameters, which are as follows: Maximum simultaneous dose Q = R 3 (V / K) 3 / a , In the formula, Q is the amount of explosives, the total amount for simultaneous blasting, and the maximum amount for delayed blasting, the unit is Kg. R is the safe allowable distance for blasting vibration, in meters; K and a are coefficients and attenuation indexes related to the terrain and geological conditions between the blasting point and the calculated protection object, and are selected according to the geological conditions of the blasting point in accordance with national standards; V is the safe permissible velocity of the seismic point where the protected object is located, in centimeters per second; When deep hole step controlled blasting is selected, the borehole diameter D is 90mm and the step height is 5 to 10m. When shallow hole step controlled blasting is selected, the borehole diameter D is 40mm and the step height is 1.5 to 3.5m.

[0008] Preferably, the deep hole step controlled blasting parameters are designed as follows: (1) Unit drug consumption q pre-take 0.35kg / m 3 During the actual construction, 1-2 test explosions and blasting vibration propagation law tests are carried out to finally determine the reasonable unit consumption of explosives. Rock emulsion explosives are selected as explosives, and the diameter of the explosive roll is configured with φ70mm emulsion explosives according to the borehole diameter D; (2) Step height H = 5-10m, select blasthole with a drilling diameter D of φ90mm; (3) Chassis resistance line W1 or minimum resistance line W, W1=(30~40)D (m) If the rock is hard, take a small value, otherwise take a large value; (4) Spacing between blastholes a = m * W1 = (0.7~1.25) W1 (m), Where, m is the blasthole density coefficient, which is 0.7 to 1.25. When W1 is selected for the front row blastholes, m is 0.7 to 0.9. (5) Blast hole spacing b = (0.70~1.0)a (m); (6) Overdrilling depth of blasthole h = (0.15-0.35) W or h = (8-15) D (m); (7) Blast hole depth L = H + h (m); (8) Charge length L1 = Q / qx, qx is the charge line density of the blasthole. For a φ90 mm blasthole, qx = 6 kg / m; (9) The filling length L2 = L-L1 should satisfy L2 ≥ (1.0-1.3) W1; (10) Hole layout: The holes are drilled vertically and arranged in a quincuncial, rectangular or square shape on the plane; (11) Calculation formula for single-hole charge Q for deep hole blasting Q=qHaW or Q=kqHab (kg) (k value is 1~1.1).

[0009] Preferably, the shallow hole step controlled blasting parameters are designed as follows: (1) Unit drug consumption q pre-take 0.3kg / m 3 During actual construction, 1 to 2 test explosions and blasting vibration propagation law tests are conducted to ultimately determine the reasonable unit consumption of explosives; (2) Chassis minimum resistance line W1 W1=(30~40)D or W1=(0.4~0.6)(m) If the rock is hard, take a small value, otherwise take a large value; (3) Spacing a between blast holes and spacing b between blast holes Hard rock blasthole spacing a = (0.7~1.2) W (m) Blast hole row spacing b = (0.8~1.0)a (m); (4) The hole arrangement method is vertical drilling and the plane is arranged in a plum blossom shape. The number of rows of holes for each blasting is controlled within 3 rows; (5) Calculation formula for single-hole charge Q for shallow hole blasting 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 amount of powder for blastholes with lateral open surfaces, and the latter formula is applicable to the calculation of the amount of powder for blastholes in each row behind multiple rows of holes.

[0010] Preferably, the smooth hole blasting parameters are designed as follows: The blasthole diameter is selected as D=90mm, and the cartridge diameter is φ=32mm; Hole spacing a = (8 ~ 14) D = 0.72 ~ 1.26m, a = 0.8m for hard rock and a = 1.0m for soft rock for test blasting; Line charge density q′, for medium and thin layers of medium-hard limestone with relatively developed cracks, q′=300g / m, and for thick layers of medium-hard limestone, q′=400g / m; Axial distribution of charge: Charge density q′ at 1.5 m at the bottom of the hole 底 = (2-4) q′ = 0.60-1.6 kg / m, take 1.2 kg / m, top 1-1.5 m line charge density q′ 顶 = (0.5~1.0) q′l=0.15~0.4kg / m, the middle is calculated according to the normal charge q′middle=0.3~0.4kg / m, the orifice plugging section l=1.2m; The uncoupling coefficient n=D / φ, the value of n is in the range of 2 to 5; Smooth hole depth L = main hole vertical depth / sinɑ, ɑ is the slope angle of the side slope, when the step height is 10m, L=12.7m; Blockage length = (12-20) D (m); The smooth hole delay main blast hole detonation time Δt ≥50ms, take 75ms; Single hole charge of smooth surface Q′: according to the formula Q′=q′×L, Kg; Hole layout: the main gun holes and buffer holes are arranged in a rectangular pattern. Structure and blocking design: The smooth hole adopts radial uncoupled charge structure, the explosives are tied to the bamboo pieces, and the detonating cord entering the manhole is tied tightly, the bamboo pieces are close to the side of the retained slope, and the blocking section of the hole is 0.8-1.5m Preferably, the charging structure for shallow hole step controlled blasting and deep hole step controlled blasting adopts continuous column charging, and smooth surface blasting adopts air interval charging. When shallow hole step controlled blasting is adopted, strip explosives and detonators are loaded into the hole, and the detonators are installed at 1 / 3 of the charge column. When φ70mm strip charge rolls are used for deep holes, they are compacted with a gun stick, and the detonators are installed at 1 / 3 and 2 / 3 of the charge column respectively.

[0011] The present invention includes at least the following beneficial effects: a deep road cutting roadbed excavation construction method of the present invention designs the road cutting excavation range and excavation support scheme according to the geological conditions, adopts a segmented and layered construction method, and sets boundary holes along the longitudinal direction of the road cutting between adjacent construction sections, and extends to set boundary through sections, sets a blocking net in the boundary through sections, and connects them as a whole through transition ropes, sets a second rope net at the top edge of the adjacent construction sections, one side of the second rope net is connected to the transition rope sleeve, and the other side is temporarily fixed to the structural surface of the adjacent construction section through fixing nails, thereby forming traction protection in the direction of the interface of excavation or blasting, and plays a role in stabilizing the boundary and adjacent construction sections during excavation construction, and blocks the dust and gravel generated by the excavation. At the same time, the setting of the boundary holes and the boundary through sections can be used as construction boundaries, and based on the drilling effect, the boundary of the current construction section can be reached faster, and all structures such as vertical poles, the first rope net, the second rope net, and the transition rope can be reused, or used as components of subsequent active protection nets, which can significantly improve construction efficiency and reduce construction costs.

[0012] Other advantages, objectives and features of the present invention will be embodied in part through the following description, and in part will be understood by those skilled in the art through study and practice of the present invention. BRIEF DESCRIPTION OF THE DRAWINGS

[0013] Figure 1 It is a layout structure diagram of the road cutting of the present invention, which is excavated in layers in sequence in the transverse cross-sectional direction; Figure 2 A side view of the arrangement of the barrier net and the second rope net structure of the present invention; Figure 3 It is a top view of the arrangement of the barrier net and the second rope net structure of the present invention; The accompanying drawings in the specification are as follows: 1. dividing hole, 2. dividing through section, 3. vertical rod, 4. first rope net, 5. transition rope, 6. second rope net, 7. ear, 8. fixing nail. DETAILED DESCRIPTION

[0014] The present invention is further described in detail below in conjunction with the accompanying drawings so that those skilled in the art can implement the invention with reference to the description.

[0015] It should be noted that the experimental methods described in the following embodiments are conventional methods unless otherwise specified, and the reagents and materials are commercially available unless otherwise specified; in the description of the present invention, the terms "lateral", "longitudinal", "upper", "lower", "front", "back", "left", "right", "vertical", "horizontal", "top", "bottom", "inside", "outside" and the like indicate orientations or positional relationships based on the orientations or positional relationships shown in the accompanying drawings, and are only for the convenience of describing the present invention and simplifying the description, and do not indicate or imply that the device or element referred to must have a specific orientation, be constructed and operated in a specific orientation, and therefore cannot be understood as a limitation on the present invention.

[0016] like Figure 1-3 As shown, the present invention provides a deep cutting roadbed excavation construction method, comprising the following steps: S1. Obtain the topographic and geological conditions of the road cutting construction, design the road cutting excavation depth and slope size range, adopt a stepped slope, graded excavation, the slope grade height is 10m, and the platform width is 2-3m; S2. Design the road cutting excavation method and slope support method. Divide the excavation area into layers horizontally and sections vertically, set up multiple excavation slopes, and set up multiple excavation layers on each excavation slope. Each excavation layer is divided into a middle section, two lateral sections and two slope sections from the middle to the sides. On the transverse section, the width of the middle section decreases from top to bottom. Before excavating the road cutting, construct a drainage ditch on the top of the cutting first; S3. Excavate in layers from top to bottom. Each excavation layer is constructed in the order from the middle to the two sides. Before construction, a row of boundary holes 1 are drilled at intervals along the longitudinal direction of the road cut at the junction of the middle section and the lateral section and at the junction of the lateral section and the slope section. Some adjacent boundary holes 1 are completely connected along the longitudinal direction of the road cut to form boundary through-sections 2. The boundary through-sections 2 are arranged at intervals. A blocking net is inserted in each boundary through-section 2. The blocking net includes a pair of vertical rods 3. A first rope net 4 is connected between the vertical rods 3. The tops of two adjacent vertical rods 3 of two adjacent first rope nets 4 are connected. There is a transition rope 5, a second rope net 6 is sleeved and connected on the transition rope 5, the second rope net 6 can rotate freely relative to the transition rope 5, a fixing nail 8 is sleeved on the side of the second rope net 6 away from the transition rope 5, the fixing nail 8 is used to temporarily drive and fix on the surface of the structure of the adjacent unconstructed section, so that the second rope net 6 can be laid flat on the surface of the adjacent unconstructed section, the first rope net 4, the second rope net 6, and the transition rope 5 are all flexible structures, after excavating a middle section or a lateral section, the blocking structure within the side range is removed, and an excavation layer is constructed, and a corresponding support structure is set on the slope of the corresponding layer; S4. Carry out slope repair, reinforcement and drainage construction.

[0017] In this project, the slopes on both sides of the cutting are divided into the high slope on the left side of K18+985-K19+400, with a slope length of 415m and a maximum slope height of 33m, the high slope on the left side of K19+400-K19+758.564, with a slope length of 358.564m and a maximum slope height of 61.4m, and the high slope on the right side of K19+460-K19+820, with a slope length of 360m and a maximum slope height of 49.3m.

[0018] The maximum height of the high slope of the left side of K18+985-K19+400 is 33m, which is a forward slope. The rock type of the slope is mainly limestone intercalated with mud dolomite, and the rock mass of the slope is Class III. The left side slope adopts a stepped slope and is excavated in stages. The graded height of the slope is 10m and the platform width is 2m. The first and second level slopes are protected by anchor frame beams, and the third level slope is protected by active nets + climbing plants. The slope ratio of the first, second and third levels is 1:0.75. The groundwater in the left high slope site is mainly pore water of Quaternary loose rocks, bedrock fissure water and karst water. The geological conditions are mainly limestone intercalated with mud dolomite, a forward slope, and the combined intersection line of L2 fissure and rock layer tends to the outside of the slope, but the inclination angle of the rock layer is relatively gentle, the inclination angle of the combined intersection line is relatively gentle, the overall slope rock mass is stable, and the slope stability is controlled by the strength of the rock mass itself.

[0019] The maximum height of the high slope of the left side of the road cutting at K19+400-K19+758.564 is 61.4m, which is a forward slope. The rock type of the slope is mainly limestone intercalated with mud dolomite, and the rock mass of the slope is Class IV. The left side slope adopts a 1:1-1:4 stepped slope, with a slope classification height of 10m and a platform width of 2m. The first-level slope is protected by anti-slide piles + shrubs and grass planting, the second and third-level slopes are protected by anchor cable frame beams, and the fourth-level slope adopts a 1:4 slope, with a slope ratio of 1:1 for the first, second and third levels. The groundwater on the left side of the high slope site is mainly pore water of Quaternary loose rocks, bedrock fissure water and karst water. The geological conditions are mainly shale intercalated with mud dolomite, the forward slope, shale and mud dolomite rock mass are relatively broken, and the slope is supported by anti-slide piles.

[0020] The maximum height of the high slope of the right side of the road cut at K19+460-K19+820 is 49.3m. It is a forward slope. The rock type of the slope is mainly limestone intercalated with mud dolomite, and the rock mass of the slope is Class IV. The right side slope adopts a 1:2.5 slope, the slope classification height is 15m, and the platform width is 2m. Shrubs and grass are used for protection of the first, second and third level slopes. The groundwater on the right side of the high slope site is mainly pore water of Quaternary loose rocks, bedrock fissure water, and karst water. The geological conditions are mainly shale intercalated with mud dolomite. The forward slope, shale, and mud dolomite rock mass are relatively broken. After excavation, the slope may slide as a whole along the rock layer, and the slope is treated by layer clearing.

[0021] The earthwork is excavated mechanically in sections and layers from top to bottom, and 30 cm of the slope is reserved for manual trimming; the stone excavation is carried out by controlled blasting and mechanical excavation. In sections near houses, high-voltage lines and other structures, mechanical excavation, shallow hole blasting and deep hole blasting are used according to the distance and blasting direction. The part near the slope is used for smooth blasting. After the blasting of the stone, a heavy excavator is used with the help of a crushing head to crush it to the diameter of the filler; the earth and stone are transported to the designated location by excavators and dump trucks. A warning area should be set up before blasting. During the blasting process, steel pipe racks or stone-blocking nets are set at the foot of the slope to ensure the safety of surrounding structures.

[0022] When excavating a high slope, the first thing to do is to construct a drainage ditch on the top of the slope. During the excavation process, the excavation surface should always maintain a drainage slope of no less than 4%, and a temporary drainage ditch should be set up to ensure smooth drainage and ensure that water can be discharged from the construction area in a timely and rapid manner. Measurement and verification work must be carried out before excavation to ensure that the slope excavation starting point is accurate and the slope opening line should be smooth.

[0023] After each excavation level, the center line, elevation and width must be remeasured to determine the opening line of the next level. A 2m ruler should be used to check the slope surface in uneven areas, and the maximum gap should not exceed 15cm. During the process, monitoring piles should be buried according to design requirements, and settlement and deformation should be monitored strictly according to the frequency.

[0024] The longitudinal direction of the cutting is the direction of its length. Figure 1 The front-to-back direction, the transverse direction of the cutting is the cross-sectional direction, Figure 1In the left and right directions, when excavating the middle section, drilling is carried out near the junction between the middle section and the lateral section. The drilling direction is consistent with the extension direction of the interface in the transverse cross-sectional direction. If stone is hit during the drilling process, the position mark is made, or the vertical rod 3 with a mark is replaced. Generally, the boundary holes 1 are arranged at equal intervals, and the decomposition through sections are arranged at equal intervals. The first rope net 4 is put on the two vertical rods 3 to form a blocking net, and a blocking net is inserted into a decomposition through section. In the direction of the interface of excavation or blasting, traction protection is carried out, and a connecting transition rope 5 is set between the two vertical rods 3 close to each other of adjacent blocking nets. Generally, the transition rope 5 is set on the top of the vertical rod 3, so as to form a section of flexible rope net in the longitudinal direction, and a row of flexible rope nets, i.e., the second rope net 6, is set on the top of the flexible rope net. The second rope net 6 can be connected in series or The commonly used length and width required for production are determined. One end of the second rope net 6 is sleeved on the transition rope 5, and the other end is laid flat on the edge side of the lateral section close to the middle section. The outer end is fixed to the lateral section by a fixing nail 8, which plays a certain fixing role. By drilling a boundary hole 1 at the junction of the construction sections and inserting a blocking net, it plays a role in stabilizing the boundary and adjacent construction sections during excavation construction, and blocks the dust and gravel generated by excavation. At the same time, the setting of the boundary hole 1 can be used as a construction boundary, which helps to grasp the boundary and the progress of construction. The corresponding marked vertical poles 3 can predict the position of the stone in advance to avoid damage to manual or mechanical equipment. All structures such as vertical poles 3, rope nets, transition ropes 5 can be reused, or used as components of subsequent active protection nets, which is conducive to improving construction efficiency and reducing construction costs.

[0025] In another technical solution, Figure 1-3 As shown, in step S3, the types of the support structure include active protection nets, anchor frame beams, and anchor cable frame beams. The first rope net 4 and the second rope net 6 have the same structure and size, and each includes a rectangular flexible rope net. A sleeve ear 7 is connected to each side or top corner of the flexible rope net, and the sleeve ear 7 is used to be mounted on the vertical rod 3 or the fixing nail 8 or the transition rope 5. The flexible rope net mounted on the vertical rod 3 forms the first rope net 4, and the flexible rope net mounted on the transition rope 5 forms the second rope net 6. After removing the blocking structure, the first rope net 4 and the second rope net 6 are removed for use as an active protection net.

[0026] By setting the first rope net 4 and the second rope net 6 to the same size structure and providing the ear 7, a standardized manufacturing structure is formed to save production costs. They can be connected in series like a puzzle as needed to obtain the required length or width range for use in subsequent active protection structures, which significantly reduces the installation and disassembly and turnover costs of the support structure and can improve the support efficiency of the corresponding position.

[0027] In another technical solution, Figure 1As shown in the figure, when excavating each excavation layer, mechanical excavation is used for earthwork, mechanical excavation, shallow hole step controlled blasting and deep hole step controlled blasting are used for stonework, and smooth blasting is used for the slope section of earthwork. According to the distance relationship between the surrounding environment and the blasting area, the blasting construction of this section must meet the following parameters, as follows: Maximum simultaneous dose Q = R 3 (V / K) 3 / a , In the formula, Q is the amount of explosives, the total amount for simultaneous blasting, and the maximum amount for delayed blasting, the unit is Kg. R is the safe allowable distance for blasting vibration, in meters; K and a are coefficients and attenuation indexes related to the terrain and geological conditions between the blasting point and the calculated protection object. They are selected according to the geological conditions of the blasting point in accordance with national standards. The reference values ​​are shown in Table 1 below. V is the safe permissible velocity of the geological point where the protected object is located, in centimeters per second, and the reference value is shown in Table 2 below; When deep hole step controlled blasting is selected, the borehole diameter D is 90mm and the step height is 5 to 10m. When shallow hole step controlled blasting is selected, the borehole diameter D is 40mm and the step height is 1.5 to 3.5m.

[0028] According to the geological conditions of the controlled explosion point and referring to relevant data, the launch tower and aqueduct are taken as: K=200, a=1.8, V=1.5cm / s. The relevant data are shown in Table 3.

[0029] Table 1 (National Standard) K and a values ​​of different lithologies in the blasting area Table 2 Blasting vibration safety allowable standard (V value) Table 3 Relationship between the distance between the blasting area and the protected object and the amount of controlled explosives per shot In another technical solution, the parameter designs for deep hole step controlled blasting, shallow hole step controlled blasting, and smooth surface blasting are specifically as follows.

[0030] The deep hole step controlled blasting parameters are designed as follows: (1) Unit drug consumption q pre-take 0.35kg / m 3 During the actual construction, 1-2 test explosions and blasting vibration propagation law tests are carried out to finally determine the reasonable unit consumption of explosives. Rock emulsion explosives are selected as explosives, and the diameter of the explosive roll is configured with φ70mm emulsion explosives according to the borehole diameter D; (2) Step height H = 5-10m, select blasthole with a drilling diameter D of φ90mm; (3) Chassis resistance line W1 or minimum resistance line W, W1=(30~40)D (m) When the rock is hard, take a smaller value, otherwise take a larger value; in this project, W1=2.7m; (4) Spacing between blastholes a = m * W1 = (0.7~1.25) W1 (m), Where, m is the blasthole density coefficient, which is 0.7 to 1.25. When W1 is selected for the front row blastholes, m is 0.7 to 0.9. (5) Blast hole spacing b = (0.70~1.0)a (m); (6) Overdrilling depth of blasthole h = (0.15-0.35) W or h = (8-15) D (m); (7) Blast hole depth L = H + h (m); (8) Charge length L1 = Q / qx, qx is the charge line density of the blasthole. For a φ90 mm blasthole, qx = 6 kg / m; (9) The filling length L2 = L-L1 should satisfy L2 ≥ (1.0-1.3) W1; (10) Hole layout: The holes are drilled vertically and arranged in a quincunx, rectangular or square shape. During construction, appropriate adjustments can be made according to the actual terrain changes. (11) Calculation formula for single-hole charge Q for deep hole blasting Q=qHaW or Q=kqHab (kg) (k value is 1~1.1).

[0031] The blasting parameters of an embodiment data are shown in Table 4: Deep hole step control blasting parameter table.

[0032] Table 4 Deep hole step controlled blasting parameters The shallow hole step controlled blasting parameters are designed as follows: (1) Unit drug consumption q pre-take 0.3kg / m 3 During actual construction, 1 to 2 test explosions and blasting vibration propagation law tests are conducted to ultimately determine the reasonable unit consumption of explosives; (2) Chassis minimum resistance line W1 W1=(30~40)D or W1=(0.4~0.6)(m) If the rock is hard, take a small value, otherwise take a large value; (3) Spacing a between blast holes and spacing b between blast holes Hard rock blasthole spacing a = (0.7~1.2) W (m) Blast hole row spacing b = (0.8~1.0)a (m); (4) The hole arrangement method is vertical drilling and the plane is arranged in a plum blossom shape. The number of rows of holes for each blasting is controlled within 3 rows; (5) Calculation formula for single-hole charge Q for shallow hole blasting 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 charge of the blasthole with the side facing the empty surface, and the latter formula is applicable to the calculation of the charge of each row of blastholes behind the multi-row holes. The blasting parameters of an embodiment data are shown in Table 5 Shallow hole step control blasting parameter table.

[0033] Table 5 Shallow hole step controlled blasting parameters The smooth hole blasting parameters are designed as follows: The blasthole diameter is selected as D=90mm, and the cartridge diameter is φ=32mm; Hole spacing a = (8 ~ 14) D = 0.72 ~ 1.26m, a = 0.8m for hard rock and a = 1.0m for soft rock for test blasting; Line charge density q′, for medium and thin layers of medium-hard limestone with relatively developed cracks, q′=300g / m, and for thick layers of medium-hard limestone, q′=400g / m; Axial distribution of charge: Charge density q′ at 1.5 m at the bottom of the hole 底 = (2-4) q′ = 0.60-1.6 kg / m, take 1.2 kg / m, top 1-1.5 m line charge density q′ 顶 = (0.5~1.0) q′l=0.15~0.4kg / m, the middle is calculated according to the normal charge q′middle=0.3~0.4kg / m, the orifice plugging section l=1.2m; The uncoupling coefficient n=D / φ, the value of n is in the range of 2 to 5; Smooth hole depth L = main hole vertical depth / sinɑ, ɑ is the slope angle of the side slope, when the step height is 10m, L=12.7m; Blockage length = (12-20) D (m); The smooth hole delay main blast hole detonation time Δt ≥50ms, take 75ms; Single hole charge of smooth surface Q′: according to the formula Q′=q′×L, Kg; Hole layout: the main gun holes and buffer holes are arranged in a rectangular pattern. Structure and blocking design: The smooth hole adopts a radial uncoupled charge structure, the explosives are tied to the bamboo pieces, and the detonating cord entering the hole is tied tightly, the bamboo pieces are close to the side of the retained slope, and the hole blocking section is 0.8-1.5m. The blasting parameters of an embodiment data are shown in Table 6 below.

[0034] Table 6 Smooth blasting parameters In another technical solution, the charging structure for shallow hole step controlled blasting and deep hole step controlled blasting adopts continuous column charging, and smooth surface blasting adopts air interval charging. When shallow hole step controlled blasting is adopted, strip explosives and detonators are loaded into the hole, and the detonators are installed at 1 / 3 of the charge column. When φ70mm strip charge rolls are used for deep holes, they are compacted to a suitable charging density with a gun stick. When the blasthole is deeper and the length of the charge in the hole is longer, the method of adding multiple detonators for detonation is adopted, and the detonators are installed at 1 / 3 and 2 / 3 of the charge column respectively.

[0035] When the environmental conditions at the location of the blasthole are relatively complex, for example, the maximum designed section charge cannot meet the vibration safety requirements by continuous charging, and when the blasthole location encounters special geological conditions such as cavities and mud layers, an interval blocking section is set. The blasthole blocking requires that the blasthole must be fully blocked except for the charging section to ensure the blocking quality. According to the "Safety Regulations for Blasting", when blasting in a complex environment, the blocking length of each blasthole should not be less than 1.2 times the average value of the chassis resistance line and the charging top resistance line. Therefore, the deep hole blasting blasthole designed in this design ensures that the hole mouth blocking length is not less than 1.2W1 or not less than 30 times the hole diameter. It requires serious and strict blocking, and its blocking quality must be guaranteed. The deep hole controlled blasting blocking can be backfilled with drilling slag and compacted with bamboo poles. Electronic digital detonators are used to perform one hole and one sound detonation from the middle to both sides with slight difference segmentation detonation. The interval time difference of the segmented delay is set to 25ms between holes and 70ms between rows. When connecting to the network, just clip all the wires of the digital electronic detonator onto the connecting bus. The delay time difference should be adjusted and designed based on the actual measured blasting vibration conditions.

[0036] Blasting safety distance verification: (1) Calculation of safety distance for individual flying rocks Based on the empirical calculation formula of individual scattered objects in deep hole blasting: Rf=20Kfn2W(m); Where Rf is the safe distance for flying rocks in open-pit blasting, m; Kf——safety factor, take 1.5; n——blasting action index, take 0.75; W——the minimum resistance line of the first row of blastholes, m; Through calculation, the maximum individual flying rock safety distance of the blasting project is estimated to be: R=20×1.5×0.752×3.0=51m.

[0037] From the scene, the estimated flying distance of deep hole blasting in the blasting area does not exceed the safety distance of the surrounding protected objects. According to the above formula and in accordance with the provisions of the "Safety Regulations for Blasting", the safety warning radius for personnel during blasting should not be less than 200m. When the road needs to be temporarily closed during blasting, the distance between the warning posts for stopping vehicles and pedestrians at both ends and the blasting point should be greater than 500m.

[0038] (2) Calculation of safe distance for blasting vibration The formula used for the calculation of blasting vibration safety distance in this design is: R= (K / V) 1 / α *Q*1 / 3 (m), Where, R is the blasting earthquake safety distance, m; this design is the distance from the boundary line of each blasting zone to the nearest protected object; Q——Total charge of the maximum section of micro-difference blasting. The maximum section charge of this design shall not exceed 77kg; V——Safety speed of blasting earthquake. There are many objects to be protected in the surrounding area, and their earthquake resistance varies. This design takes 1.0cm / s for ordinary houses and 2.0cm / s or less for communication towers for vibration safety verification.

[0039] K, α——are the correlation coefficient and attenuation index of the blasting medium. According to the on-site investigation and the experience of similar projects, K is taken as 200 and α is taken as 1.8. When considering the poor quality buildings, K is taken as 200 and α is taken as 1.8. The verification results of the safe distance of blasting vibration are shown in Table 7.

[0040] Table 7 Blasting vibration safety distance verification results According to the calculation in the above table, the safe range of vibration caused by the maximum amount of explosives controlled by the design in each area is smaller than the actual minimum distance from the blasting area to the objects to be protected, so the designed blasting parameters are reasonable.

[0041] Although the embodiments of the present invention have been disclosed as above, they are not limited to the applications listed in the specification and the implementation modes, and they can be fully applied to various fields suitable for the present invention. For those familiar with the art, additional modifications can be easily implemented. Therefore, without departing from the general concept defined by the claims and the scope of equivalents, the present invention is not limited to the specific details and the illustrations shown and described herein.

Claims

1. A deep cutting roadbed excavation construction method, characterized in that: The steps include: S1. Obtain the topographic and geological conditions of the road cutting construction, design the road cutting excavation depth and slope size range, adopt a stepped slope, graded excavation, the slope grade height is 10m, and the platform width is 2-3m; S2. Design the road cutting excavation method and slope support method. Divide the excavation area into layers horizontally and sections vertically, set up multiple excavation slopes, and set up multiple excavation layers on each excavation slope. Each excavation layer is divided into a middle section, two lateral sections and two slope sections from the middle to the sides. On the transverse section, the width of the middle section decreases from top to bottom. Before excavating the road cutting, construct a drainage ditch on the top of the cutting first; S3. Excavate in layers from top to bottom. Each excavation layer is constructed in the order from the middle to the two sides. Before construction, a row of boundary holes are drilled at intervals along the longitudinal direction of the road cut at the junction of the middle section and the lateral section and at the junction of the lateral section and the slope section. Some adjacent boundary holes are completely connected along the longitudinal direction of the road cut to form boundary through sections. The boundary through sections are arranged at intervals. A blocking net is inserted in each boundary through section. The blocking net includes a pair of vertical bars. A first rope net is connected between the vertical bars. Between the tops of the two adjacent vertical bars of the two adjacent first rope nets, a first rope net is inserted between the tops of the two adjacent vertical bars of the two adjacent first rope nets. A transition rope is connected, and a second rope net is sleeved on the transition rope. The second rope net 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 fix it on the surface of the structure 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 blocking structure within the side range is removed, and a corresponding support structure is set on the slope of the corresponding layer when constructing an excavation layer; S4. Carry out slope repair, reinforcement and drainage construction.

2. The deep cutting roadbed excavation construction method according to claim 1, characterized in that: In step S3, the types of support structures include active protective nets, anchor frame beams, and anchor cable frame beams. The first rope net and the second rope net have the same structure and size, and each includes a rectangular flexible rope net. A sleeve ear is connected to each side or top corner of the flexible rope net, and the sleeve ear is used to be mounted on the vertical pole or the fixing nail or the transition rope. The flexible rope net mounted on the vertical pole forms the first rope net, and the flexible rope net mounted on the transition rope forms the second rope net. After removing the blocking structure, the first rope net and the second rope net are removed for use as an active protective net.

3. The deep cutting roadbed excavation construction method according to claim 2, characterized in that: When excavating each excavation layer, mechanical excavation is used for earthwork, mechanical excavation, shallow hole step controlled blasting and deep hole step controlled blasting are used for stonework, and smooth blasting is used for the slope section of earthwork. According to the distance relationship between the surrounding environment and the blasting area, the blasting construction of this section must meet the following parameters, as follows: Maximum simultaneous dose Q = R 3 (V / K) 3 / a , In the formula, Q is the amount of explosives, the total amount for simultaneous blasting, and the maximum amount for delayed blasting, the unit is Kg. R is the safe allowable distance for blasting vibration, in meters; K and a are coefficients and attenuation indexes related to the terrain and geological conditions between the blasting point and the calculated protection object, and are selected according to the geological conditions of the blasting point in accordance with national standards; V is the safe permissible velocity of the seismic point where the protected object is located, in centimeters per second; When deep hole step controlled blasting is selected, the borehole diameter D is 90mm and the step height is 5 to 10m. When shallow hole step controlled blasting is selected, the borehole diameter D is 40mm and the step height is 1.5 to 3.5m.

4. The deep cutting roadbed excavation construction method according to claim 3, characterized in that: The deep hole step controlled blasting parameters are designed as follows: (1) Unit drug consumption q pre-take 0.35kg / m 3 During the actual construction, 1-2 test explosions and blasting vibration propagation law tests are carried out to finally determine the reasonable unit consumption of explosives. Rock emulsion explosives are selected as explosives, and the diameter of the explosive roll is configured with φ70mm emulsion explosives according to the borehole diameter D; (2) Step height H = 5-10 m, select blasthole with a drilling diameter D of φ90 mm; (3) Chassis resistance line W1 or minimum resistance line W, in meters, W1=(30~40)D If the rock is hard, take a small value, otherwise take a large value; (4) Spacing between blast holes a = m * W1 = (0.7~1.25) W1, Where, m is the blasthole density coefficient, ranging from 0.7 to 1.

25. When W1 is selected for the front row blastholes, m is 0.7 to 0.

9. (5) Blast hole spacing b = (0.70~1.0)a; (6) Overdrilling depth of blasthole h = (0.15-0.35)W or h = (8-15)D; (7) Blast hole depth L = H + h (m); (8) Charge length L1 = Q / qx, qx is the charge line density of the blasthole. For a φ90 mm blasthole, qx = 6 kg / m; (9) The filling length L2 = L-L1 should satisfy L2 ≥ (1.0-1.3) W1; (10) Hole layout: The holes are drilled vertically and arranged in a quincuncial, rectangular or square shape on the plane; (11) Calculation formula for single-hole charge Q for deep hole blasting Q=qHaW or Q=kqHab (kg), the k value is 1~1.

1.

5. The deep cutting roadbed excavation construction method according to claim 3, characterized in that: The shallow hole step controlled blasting parameters are designed as follows: (1) Unit drug consumption q pre-take 0.3kg / m 3 During actual construction, 1 to 2 test explosions and blasting vibration propagation law tests are conducted to ultimately determine the reasonable unit consumption of explosives; (2) Chassis minimum resistance line W1 W1=(30~40)*D or W1= 0.4~0.6 m If the rock is hard, take a small value, otherwise take a large value; (3) Spacing a between blast holes and spacing b between blast holes Hard rock blasthole spacing a = (0.7 ~ 1.2) W; Blast hole row spacing b = (0.8~1.0)a; (4) The hole arrangement method is vertical drilling and the plane is arranged in a plum blossom shape. The number of rows of holes for each blasting is controlled within 3 rows; (5) Calculation formula for single-hole charge Q for shallow hole blasting 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 amount of powder for blastholes with lateral open surfaces, and the latter formula is applicable to the calculation of the amount of powder for blastholes in each row behind multiple rows of holes.

6. The deep cutting roadbed excavation construction method according to claim 3, characterized in that: The smooth hole blasting parameters are designed as follows: The blasthole diameter is selected as D=90mm, and the cartridge diameter is φ=32mm; Hole spacing a = (8 ~ 14) D = 0.72 ~ 1.26 m, a = 0.8m for hard rock and a = 1.0m for soft rock for test blasting; Line charge density q′, for medium and thin layers of medium-hard limestone with relatively developed cracks, q′=300g / m, and for thick layers of medium-hard limestone, q′=400g / m; Axial distribution of charge: Charge density q′ at 1.5 m at the bottom of the hole 底 = (2-4) q′ = 0.60-1.6 kg / m, take 1.2 kg / m, top 1-1.5 m line charge density q′ 顶 = (0.5~1.0) q′l=0.15~0.4kg / m, the middle is calculated according to the normal charge q′middle=0.3~0.4kg / m, the orifice plugging section l=1.2m; The uncoupling coefficient n=D / φ, the value of n is in the range of 2 to 5; Smooth hole depth L = main hole vertical depth / sinɑ, ɑ is the slope angle of the side slope, when the step height is 10m, L=12.7m; Blockage length = (12-20) D; The smooth hole delay main blast hole detonation time Δt ≥50ms, take 75ms; Single hole charge of smooth surface Q′: according to the formula Q′=q′×L, Kg; Hole layout: the main gun holes and buffer holes are arranged in a rectangular pattern. Structure and blocking design: The smooth hole adopts a radial uncoupled charging structure. The explosives are tied to bamboo pieces, and the detonating cord entering the manhole is tied tightly. The bamboo pieces are close to the retained slope side, and the blocking section of the hole mouth is 0.8-1.5m.

7. The deep cutting roadbed excavation construction method according to claim 3, characterized in that: The charging structure for shallow hole step controlled blasting and deep hole step controlled blasting adopts continuous column charging, and smooth surface blasting adopts air interval charging. When shallow hole step controlled blasting is adopted, strip explosives and detonators are loaded into the hole, and the detonators are installed at 1 / 3 of the charge column. When φ70mm strip charge rolls are used for deep holes, they are compacted with a gun stick, and the detonators are installed at 1 / 3 and 2 / 3 of the charge column respectively.

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