Road protection anchoring pile construction method

Abstract

The invention relates to the technical field of anchor pile construction, and discloses a road protection anchor pile construction method. The construction method of the road protection anchoring pile comprises the following steps: surveying and setting out; protection facility installation and construction; performing hole digging construction; the hole digging construction comprises the steps that manual excavation is conducted on stratums such as silty clay, coarse gravel soil, gravelly soil and a pebble bed, and machine crushing excavation is conducted on hard rocks of a weathered layer and a middle weathered layer; blasting excavation is conducted on hard strong-weathering sandstone, medium-weathering sandstone and the like; mounting a retaining wall template; pouring retaining wall concrete; and sealing the bottom of the end hole. According to different rock stratum hardness, different excavation modes are adopted; and blasting excavation is adopted for hard rock stratums, and the excavation speed can be increased.

Description

Technical Field

[0001] This invention relates to the field of anchor pile construction technology, and in particular to a method for constructing highway protection anchor piles. Background Technology

[0002] In existing highway construction, it is often necessary to install anchor piles on slopes to support the road. For slope anchor piles (i.e., anchor piles installed on slopes), to reduce the impact on the highway and the mountainside during construction, mechanical excavation or water-jet drilling is generally used. However, this excavation method is affected by the hardness of the rock strata and is generally suitable for rock strata with lower hardness. Furthermore, this construction method is slow, prolonging the entire construction process. Therefore, how to improve the construction speed of anchor piles is an urgent problem that the industry needs to solve. Summary of the Invention

[0003] This invention provides a method for constructing highway protective anchor piles, which solves the problem of slow construction progress of anchor piles in the prior art.

[0004] This invention provides a method for constructing highway protective anchor piles, comprising: Measurement and layout; Construction of protective facilities installation; Hole excavation construction; the hole excavation construction includes: For strata such as silty clay, coarse gravelly soil, gravelly soil, and pebble layer, manual excavation is carried out; For the weathered and moderately weathered hard rock layers, mechanical crushing and excavation are carried out; For hard, strongly weathered sandstone and moderately weathered sandstone, blasting excavation is carried out; Wall retaining formwork installation; Concrete pouring for wall protection; Final hole sealing.

[0005] According to the highway protection anchor pile construction method provided by the present invention, the step of blasting excavation for harder, strongly weathered sandstone and moderately weathered sandstone includes: When the borehole depth enters a strongly weathered sandstone layer and the distance from the bottom of the pile is outside the safe threshold range, blasting is used for excavation. Within the safe threshold range of the bottom elevation, excavation is carried out manually, removing material at every point.

[0006] According to the highway protection anchor pile construction method provided by the present invention, when the hole depth enters the strongly weathered sandstone layer and the distance from the pile bottom elevation is outside the safety threshold range, the method of blasting excavation includes: The hole layout and drilling operations are carried out according to the blasting design, wherein the hole layout adopts a quincunx pattern. After loading and plugging are completed, network connections are made according to the blasting design, and the joints are wrapped with insulating tape. Protective measures should be taken in accordance with the protection range and measures in the blasting design. Before blasting, the blasting blanket should be fixed to the hole opening and sandbags should be used to weigh it down.

[0007] According to the highway protection anchor pile construction method provided by the present invention, in the step of carrying out protection according to the protection range and protection measures in the blasting design, before blasting, fixing the blasting blanket at the borehole opening and pressing the blasting blanket with sandbags, the method further includes: The blasting was carried out using a micro-delay blasting method with sequential hole-by-hole detonation.

[0008] According to the highway protection anchor pile construction method provided by the present invention, after the loading and plugging are completed, network connections are made according to the blasting design, and the joints are wrapped with insulating tape, including: For areas where the surrounding environment has requirements regarding blasting vibration and flyrock, a hole-by-hole initiation network is adopted.

[0009] According to the highway protection anchor pile construction method provided by the present invention, the explosive is an emulsion explosive.

[0010] According to the highway protection anchor pile construction method provided by the present invention, the installation of the retaining wall formwork includes: After drilling, acrylic sheets are laid on the anchor pile retaining wall according to the exposed length of the anchor pile.

[0011] According to the highway protection anchor pile construction method provided by the present invention, the concrete pouring of the retaining wall includes: When there is no water or the water volume in the hole is small, install a concrete tremie pipe to the bottom of the hole. The bottom of the tremie pipe should not be more than the second safety distance from the bottom of the hole. Then start pouring the core concrete.

[0012] The highway protection anchor pile construction method provided by the present invention further includes, before the concrete pouring of the retaining wall: Reinforcing cage fabrication, hoisting, and sonic logging pipe installation.

[0013] The highway protection anchor pile construction method provided by this invention adopts different excavation methods according to different rock layer hardness; and for harder rock layers, blasting excavation is used to improve the excavation speed. Attached Figure Description

[0014] To more clearly illustrate the technical solutions in this invention or the prior art, the drawings used in the description of the embodiments or the prior art will be briefly introduced below. Obviously, the drawings described below are some embodiments of this invention. For those skilled in the art, other drawings can be obtained from these drawings without creative effort.

[0015] Figure 1This is a flowchart illustrating the construction method for highway protection anchor piles provided by the present invention.

[0016] Figure 2 This is one of the schematic diagrams of the detonation network used in this invention.

[0017] Figure 3 This is one of the schematic diagrams of the continuous charge structure provided by the present invention.

[0018] Figure 4 This is one of the schematic diagrams of borehole distribution provided by the present invention.

[0019] Figure 5 This is the second schematic diagram of the borehole distribution provided by the present invention.

[0020] Figure 6 This is the third schematic diagram of the borehole distribution provided by the present invention.

[0021] Figure 7 This is the fourth schematic diagram of the borehole distribution provided by the present invention. Detailed Implementation

[0022] To make the objectives, technical solutions, and advantages of this invention clearer, the technical solutions of this invention will be clearly and completely described below with reference to the accompanying drawings. Obviously, the described embodiments are only some, not all, of the embodiments of this invention. All other embodiments obtained by those skilled in the art based on the embodiments of this invention without creative effort are within the scope of protection of this invention.

[0023] like Figure 1 As shown in the figure, a specific embodiment of the present invention provides a method for constructing highway protection anchor piles. This method for constructing highway protection anchor piles includes: S100, Measurement and layout.

[0024] Furthermore, construction preparation is required before surveying and setting out. Construction preparation includes: Level the ground around the well opening and install surface drainage, seepage prevention facilities, and guardrails to prevent falling objects; lock the well opening and cover it with a well cover. Prepare all necessary machinery, equipment, and underground drainage, ventilation, and lighting facilities for each process. Ensure that the pile-digging equipment, construction water supply, and electrical safety protection facilities are installed as required.

[0025] Furthermore, the measurement and layout process includes: The construction site is leveled and debris is removed before construction layout. Pile positions are determined according to the design drawings, and cross-shaped retaining piles are installed, extending beyond the excavation area for verification during construction. Drainage, ventilation, and lighting equipment are prepared for the borehole.

[0026] S200, Installation of protective facilities.

[0027] Furthermore, the installation of protective facilities includes the installation of interlocking seams. Interlocking seam installation includes: Based on the surveyed and laid-out pile positions, excavation of the interlocking joints is carried out. Reinforcing steel bars for the interlocking joints and retaining walls are tied, formwork is erected, the formwork is checked and reinforced, and then concrete is poured into the interlocking joints and retaining walls. The joints of the interlocking joints and retaining walls must not be located at the bottom layer boundary or sliding surface.

[0028] After the locking hole is drilled, a vertical transport support is erected at the top of the pile hole. On the side away from the locking hole, piles of equal height and considerable length are constructed together with the locking hole to form a platform for placing the lifting equipment, ensuring the stable and secure erection of the lifting equipment.

[0029] S300, Borehole excavation; Borehole excavation includes: For strata such as silty clay, coarse gravelly soil, gravelly soil, and pebble layer, manual excavation is carried out; For the weathered and moderately weathered hard rock layers, mechanical crushing and excavation are carried out; For hard, strongly weathered sandstone and moderately weathered sandstone, blasting excavation is carried out.

[0030] In this embodiment, the excavation is carried out on one side of the road within the mountainside, for example, on the side of a winding mountain road. In other words, holes are excavated in the mountainside, with the holes located on one side of the road and spaced apart from it. The upper section of the hole is above the road, and the lower section is below the road.

[0031] For the upper section of the borehole, which consists of relatively hard, strongly weathered sandstone and moderately weathered sandstone, blasting excavation is carried out. The spacing, depth, and number of boreholes can be adjusted to ensure that the blasting operation does not impact the mountain or road.

[0032] In this embodiment, different excavation methods are adopted according to different rock layer hardness; and blasting excavation is used for harder rock layers to increase the excavation speed.

[0033] Furthermore, the drilling construction methods include: (1) Excavation of the first section of the bored pile: The excavated waste from the pile hole is manually transported out of the pile. After the first segment of the pile is excavated, a plumb bob is suspended at the intersection of the cross-shaped pile supports. The plumb bob is used to check the hole diameter, verticality, and center deviation. This ensures that the center of the formed hole is on the same vertical line as the center of the pile.

[0034] (2) Retaining wall construction: Centralized mixing and transportation to the site. Steel composite formwork is used, and the wall reinforcement is installed using a method of unified prefabrication and installation in the processing area. The vertical reinforcement of the wall is connected by single-sided lap welding, and the connection between the circumferential reinforcement and the vertical reinforcement is tied.

[0035] The retaining wall formwork is assembled from small steel formwork. It is made in sections according to the cross-sectional size of the pile hole and the excavation progress. It is assembled inside the hole and connected and fixed with the pre-assembled steel pipe frame, top support, bottom support and fasteners to achieve the purpose of rapid construction.

[0036] (3) The method for the second section of the bored pile is the same as that for the first section, until the depth of the pile hole reaches the preset depth.

[0037] Furthermore, for harder, strongly weathered sandstone and moderately weathered sandstone, blasting excavation is carried out, including: When the borehole depth enters a strongly weathered sandstone layer and the distance from the bottom of the pile is outside the safe threshold range, blasting is used for excavation. Within the safe threshold range of the bottom elevation, excavation is carried out manually, removing material at every point.

[0038] Specifically, for harder, strongly weathered sandstone and moderately weathered sandstone, handheld pneumatic drills are used to drill blasting holes. When the hole depth reaches the strongly weathered rock layer, manual excavation becomes difficult. In this case, weak vibration blasting can be used for excavation. The amount of explosives and the depth of penetration must be controlled, and blasting operations must not be carried out within 50cm of the pile bottom elevation. This is to avoid affecting the quality of the retaining wall of the hole itself and adjacent piles, as well as the pile formation quality of adjacent piles. Manual chiseling should be used to excavate to the required depth to prevent loosening of the hole bottom and affecting the bearing capacity of the foundation.

[0039] Furthermore, when the borehole depth enters a strongly weathered sandstone layer and the distance from the pile bottom elevation is outside the safe threshold range, blasting is used for excavation, including: The drilling and hole layout were carried out according to the blasting design, with the hole layout using a quincunx pattern. After loading and plugging are completed, network connections are made according to the blasting design, and the joints are wrapped with insulating tape. Protective measures should be taken in accordance with the protection range and measures in the blasting design. Before blasting, the blasting blanket should be fixed to the hole opening and sandbags should be used to weigh it down.

[0040] Specifically, the blasting excavation process includes: (1) Construction preparation The bottom of the hole to be blasted is cleaned to meet the needs of the drilling equipment, and the scope and depth of the drilling operation are determined.

[0041] (2) Drilling operation Under the guidance of the blasting personnel, the drilling and hole layout were carried out strictly in accordance with the blasting design. The hole layout mainly adopted a quincunx pattern based on the actual terrain conditions.

[0042] The plugging material consisted of drilled clay, which was then tamped down with wooden poles, and an emulsion-waterproof explosive was used.

[0043] (3) Explosive network laying After loading and plugging are completed, network connections must be made strictly in accordance with the blasting design to prevent omissions or incorrect connections, and joints must be wrapped with insulating tape.

[0044] (4) Explosion protection Protective measures should be implemented in accordance with the protection range and measures in the blasting design. Before blasting, the explosive charge should be fixed at the wellhead and sandbags should be used to weigh it down to ensure that flying rocks do not fly out of the wellhead during the blasting process.

[0045] (5) Set up warning and detonation After the blast, sufficient ventilation and waiting time should exceed 15 minutes.

[0046] Furthermore, for areas with abundant rainfall, No. 2 rock emulsion explosive is selected.

[0047] Furthermore, electronic detonators are selected as the detonating equipment. Dedicated digital electronic detonators, dedicated digital electronic detonator initiators, and blasting busbars are used to detonate the explosive charges. This method is safe, convenient, and easy to operate, facilitating the control of the flow of civilian explosives. It is also a blasting equipment promoted for use by the state.

[0048] Furthermore, in accordance with the protection range and measures specified in the blasting design, before blasting, the blasting blanket is fixed to the borehole opening and sandbags are used to weigh it down. This also includes: The blasting was carried out using a sequential, low-delay detonation method. This reduces the impact of the explosion on the highway.

[0049] Furthermore, after loading and plugging are completed, network connections are made according to the blasting design, and the joints are wrapped with insulating tape, including: For areas where the surrounding environment is sensitive to blasting vibrations and flyrock, a sequential detonation network is used. This can reduce the impact of the explosion on the highway.

[0050] In some embodiments, blasting network design and blasting construction: Design of Millisecond Delay Time: To improve blasting effect and reduce blasting vibration, a micro-delay blast is implemented between explosive charges. The detonation sequence and delay time of each chamber are determined by calculation and in conjunction with the nominal time of each section of the finished detonator. From the perspective of improving fragmentation effect, the micro-delay time t between the front and rear rows of explosive charges should be equal to or close to the time t1 required for the blasted object borne by the front row of explosive charges to have moved and the free surface of the rear row of explosive charges to have formed. This ensures that the rear row of explosive charges detonates after the front row reaches its maximum projectile velocity, and the rear row of explosive charges follows and impacts the front row as closely as possible, reducing energy leakage and improving fragmentation effect. From the perspective of blasting vibration safety, the micro-delay time between explosive charges should be greater than or equal to the micro-delay time t2 required to separate the main shock waves caused by the explosions of adjacent explosive charges, so that the seismic waves from the explosions of the front and rear explosive charges do not overlap when they reach the protected object, thus reducing vibration. That is: t = t1; t ≥ t2. Based on past experience and research results, t = 25~100ms is chosen. This design, after numerous tests, will not disturb the mountain, and the interior of the pile will achieve the desired shape. At most, it will occasionally require an electric pick to level and modify it. It will not cause excessive over-excavation of the pile interior due to excessive explosives, excessive concrete usage, or excessively long wall pouring time, nor will it require supplementary blasting or under-excavation using electric picks or water-milled bricks due to insufficient explosives, thus affecting the overall construction progress. This method ensures construction quality and improves construction progress.

[0051] In some embodiments, the brute-force network design includes: Depending on the engineering geological conditions of the rock and the surrounding environment, continuous or intermittent charging can be flexibly adopted, and the borehole opening should be sealed tightly with drilling mud or rock powder.

[0052] This project employs a continuous charging structure, with one digital electronic detonator inserted into each borehole. Explosives are continuously loaded along the axial direction of the borehole. For shallow-hole blasting, a single detonating charge is typically used. Its advantages are simple operation; its disadvantages are a lower charge height, which can easily result in large fragments forming at the borehole opening where no explosive charge is present.

[0053] For areas where the surrounding environment has requirements regarding blasting vibration and flyrock, a sequential detonation network is used to achieve the control requirements. For example... Figure 2 As shown. Each hole is equipped with one digital electronic detonator. The delay interval for each hole is controlled within 50~150ms. A dedicated blasting busbar is used for parallel initiation outside the hole.

[0054] In some embodiments, blasting operations include: (1) Charge structure Deep-hole bench loosening blasting uses Φ70 (d=90mm) emulsion explosive cartridges as the initiating explosive, with No. 2 rock emulsion explosive as the main explosive, and drill cuttings or sand-clay as the plugging material. The initiating explosive charge is located at the same level as the top surface of the lower bench.

[0055] Shallow hole blasting uses Φ32 tubular emulsion explosive as the main explosive, loaded in a whole roll at the bottom, with the detonator placed at the bottom of the borehole. Drill cuttings or sand and clay are used for plugging.

[0056] (2) Detonation method The method of sequential micro-delay blasting is adopted, and various blasting modes are used depending on the working face conditions and environmental conditions. The micro-delay interval t is determined by comprehensively considering factors such as blasting method, vibration control and fragmentation quality, and is generally taken as t=25~100ms, gradually increasing from the beginning to the end.

[0057] (3) Initiation Network For large-scale deep-hole bench controlled blasting, digital electronic detonators in parallel initiation networks were used for all blasting operations. (4) Charge and packing design: A continuous coupled charge structure is adopted, such as... Figure 3 As shown, the continuous coupling charge structure includes a barrel, filled from top to bottom with stemming material, kraft paper and other packing materials, and the main explosive; the continuous coupling charge structure also includes a detonator and a detonating tube; the detonator is embedded in the main explosive, one end of the detonating tube is connected to the detonator, and the other end extends to the outside of the barrel. Ignition of the detonating tube causes the detonator to explode, thereby causing the entire continuous coupling charge structure to explode.

[0058] In some embodiments, pile foundation demolition is carried out by blasting. The following description uses anchor piles of different sizes as examples.

[0059] For example, consider an anchor pile with dimensions of 1.5m × 2.5m: (1) Hole depth L The anchor pile is 1.5m × 2.5m. The hole depth L is 0.6-0.8 times the shorter side of the working face. According to the rock structure, it is taken as 0.8L: that is, L = 1.5 × 0.8 = 1.2m. The groove hole is 0.3m deeper than the target depth, so the groove hole L = 1.5m.

[0060] Hole utilization rate η and cycle advance.

[0061] The borehole utilization rate η is generally 0.8-0.95; we take 0.85.

[0062] The cyclic advance length l = L × η = 1.2 × 0.85 = 1.0 m.

[0063] (2) Specific consumption q Referring to the robustness coefficient (ƒ=7-17), the unit dosage coefficient of the pile foundation is determined by looking up a table, q=1.5~2.0 (kg / m). 3 Take 2.0 kg / m 3 The principle of drilling more holes and loading less explosives should be followed to reduce the disturbance of the foundation caused by blasting vibrations.

[0064] Number of boreholes N, The distribution of the 22 blast holes is as follows Figure 4 As shown.

[0065] In the formula: N: is the number of boreholes; q—Explosive consumption per unit, kg / m³ 3 ; S—Tunneling cross-sectional area; γ—charge density per unit length of borehole (kg / m).

[0066] (3) Total charge Q per cycle: Anchor pile 1.5m×2.5m: Q=q·S·L·η=2.0×5.5×1.2×0.8≈10.6kg.

[0067] Q—Amount of explosives required per tunneling cycle, in kg; q—Explosive consumption per unit, kg / m³ 3 ; S—Tunneling cross-sectional area; L—average borehole depth, m; η—Borehole utilization rate.

[0068] (4) Single-hole charge: The average charge per hole is Q0 = Q / N = 10.6 ÷ 22 ≈ 0.5 kg. Generally, the slotted holes are filled with 20-30% more charge, while the peripheral holes are filled with 10-20% less charge.

[0069] The charge amount per auxiliary hole is Q2 = 1.0 × 0.5 = 0.5 kg, so we take Q2 = 0.5 kg.

[0070] The weight of the peripheral hole Q3 is 0.8 × 0.5 = 0.4 kg, so we take Q3 = 0.4 kg.

[0071] The charge amount per slotted hole is Q1 = 1.3 × 0.5 = 0.65 kg, so we take Q1 = 0.7 kg.

[0072] The total charge for a single blast is approximately 4Q1 + 4Q2 + 14Q3 ≈ 10.4 kg. Take a whole package of explosives weighing 10 kg.

[0073] For example, consider an anchor pile with dimensions of 2.5m × 3.5m: (1) Hole depth L The anchor pile is 2.5m × 3.5m. The hole depth L is 0.6-0.8 times the shorter side of the working face. Based on the rock structure, we take 0.6L: that is, L = 2.5 × 0.6 = 1.5m. The groove hole is 0.3m deeper than the target depth, so L = 1.8m.

[0074] (2) Hole utilization rate η and cycle advance The borehole utilization rate η is generally 0.8-0.95; we take 0.9.

[0075] The cyclic advance length l = L × η = 1.5 × 0.9 = 1.35 m.

[0076] (3) Specific consumption q Referring to the robustness coefficient (ƒ=7-17), the unit dosage coefficient of the pile foundation is determined by looking up a table, q=1.5~2.0 (kg / m). 3 Take 1.6 kg / m 3 The principle of drilling more holes and loading less explosives should be followed to reduce the disturbance of the foundation caused by blasting vibrations.

[0077] (4) Number of boreholes N, The distribution of the 30 blast holes is as follows: Figure 5 .

[0078] In the formula: N: is the number of boreholes; q—Explosive consumption per unit, kg / m³ 3 ; S—Tunneling cross-sectional area; γ—charge density per unit length of borehole (kg / m).

[0079] (5) Total charge Q per cycle Q=q·S·L·η=1.6×11.3×1.5×0.8≈22kg.

[0080] Q—Amount of explosives required per tunneling cycle, in kg; q—Explosive consumption per unit, kg / m³ 3 ; S—Tunneling cross-sectional area.

[0081] L—average borehole depth, m; η—Borehole utilization rate.

[0082] Single-hole charge: The average charge per hole is Q0 = Q / N = 22 ÷ 30 ≈ 0.73 kg. Generally, the slotted holes are filled with 20-30% more charge, while the peripheral holes are filled with 10-30% less charge.

[0083] The charge amount per auxiliary hole is Q2 = 1.0 × 0.73 = 0.73 kg, so we take Q2 = 0.8 kg.

[0084] The peripheral hole Q3 = 0.8 × 0.73 = 0.58 kg, so we take Q3 = 0.6 kg.

[0085] The charge amount per slotted hole is Q1 = 1.3 × 0.73 = 0.95 kg, so we take Q1 = 1.0 kg.

[0086] The total explosive charge for a single blast is approximately 4Q1 + 8Q2 + 18Q3 ≈ 21.2 kg. Rounding down to 21 kg, this is the total explosive charge.

[0087] For example, consider an anchor pile with dimensions of 2.0m × 3.0m: (1) Hole depth L The hole depth L is taken as 0.6-0.8 times the shorter side of the working face. Based on the rock structure, we take 0.8L: that is, L=2.0×0.8=1.6m. If the groove hole is 0.3m deeper, then L=1.9m.

[0088] (2) Hole utilization rate η and cycle advance The borehole utilization rate η is generally 0.8-0.95; we take 0.85.

[0089] The cyclic advance length l = L × η = 1.6 × 0.85 = 1.4 m.

[0090] (3) Specific consumption q Referring to the robustness coefficient (ƒ=7-17), the unit dosage coefficient of the pile foundation is determined by looking up a table, q=1.5~2.0 (kg / m). 3 Take 1.7 kg / m 3 The principle of drilling more holes and loading less explosives should be followed to reduce the disturbance of the foundation caused by blasting vibrations.

[0091] (4) Number of boreholes N, The distribution of the 28 blast holes is as follows Figure 6 .

[0092] In the formula: N: is the number of boreholes; q—Explosive consumption per unit, kg / m³ 3 ; S—Tunneling cross-sectional area; — Charge density per unit length of blast hole (kg / m).

[0093] (5) Total charge Q per cycle Q=q·S·L·η=1.7×8.16×1.6×0.9≈19kg.

[0094] Q—Amount of explosives required per tunneling cycle, in kg; q—Explosive consumption per unit, kg / m³ 3 ; S—Tunneling cross-sectional area; L—average borehole depth, m; η—Borehole utilization rate.

[0095] Single-hole charge The average charge per hole is Q0 = Q / N = 19 ÷ 28 ≈ 0.7 kg. Generally, the slotted holes are filled with 20-30% more explosive and the peripheral holes are filled with 10-30% less explosive.

[0096] The charge amount per auxiliary hole is Q2 = 1.0 × 0.7 = 0.7 kg, so we take Q2 = 0.8 kg.

[0097] The weight of the peripheral hole Q3 is 0.8 × 0.7 = 0.5 kg, so we take Q3 = 0.5 kg.

[0098] The charge amount per slotted hole is Q1 = 1.3 × 0.7 = 0.9 kg, so we take Q1 = 1.0 kg.

[0099] The total charge for a single blast is approximately 4Q1 + 8Q2 + 16Q3 ≈ 18.4 kg. Therefore, we take the total charge of the entire explosive package as 18 kg.

[0100] For example, consider an anchor pile with dimensions of 3.0m × 4.0m: (1) Hole depth L The hole depth L is taken as 0.6-0.8 times the shorter side of the working face. Based on the rock structure, we take 0.6L: that is, L=3.0×0.6=1.8m. If the groove hole is 0.2m deeper, then L=2m.

[0101] (2) Hole utilization rate η and cycle advance The borehole utilization rate η is generally 0.8-0.95; we take 0.9.

[0102] The cyclic advance length l = L × η = 1.8 × 0.9 = 1.62 m.

[0103] (3) Specific consumption q Referring to the robustness coefficient (ƒ=7-17), the unit dosage coefficient of the pile foundation is determined by looking up a table, q=1.5~2.0 (kg / m). 3 Take 1.5 kg / m³. (4) Number of boreholes N, The distribution of the 44 gun holes is as follows Figure 7 .

[0104] In the formula: N: is the number of boreholes; q—Explosive consumption per unit, kg / m³ 3 ; S—Tunneling cross-sectional area; — Charge density per unit length of blast hole (kg / m).

[0105] (5) Total charge Q per cycle Q=q·S·L·η=1.5×15×1.8×0.9≈36.45kg.

[0106] Q—Amount of explosives required per tunneling cycle, in kg; q—Explosive consumption per unit, kg / m³ 3 ; S—Tunneling cross-sectional area.

[0107] L—average borehole depth, m; η—Borehole utilization rate.

[0108] Single-hole charge The average charge per hole is Q0 = Q / N = 36.45 ÷ 41 ≈ 0.89 kg. Generally, the slotted holes are filled with 20-30% more charge, while the peripheral holes are filled with 10-30% less charge.

[0109] The charge amount per auxiliary hole is Q2 = 1.0 × 0.89 = 0.89 kg, so we take Q2 = 0.89 kg.

[0110] The peripheral hole Q3 = 0.8 × 0.89 = 0.712 kg, so we take Q3 = 0.7 kg.

[0111] The charge capacity per slotted hole is Q1 = 1.3 × 0.89 = 1.2 kg, so we take Q1 = 1.2 kg.

[0112] The total charge for a single blast is approximately 9Q1 + 12Q2 + 20Q3 ≈ 48.8 kg. Taking the total charge of the entire explosive package as 35.48 kg...

[0113] In some embodiments, machine construction includes water-jet drilling.

[0114] Water-jet drilling operations are conducted in a manner that is not explicitly stated in the text. A water-jet drill primarily consists of three parts: a drilling rig, a drilling cylinder, and a specialized water pump. For strata such as gravel and pebble layers, excavation is performed layer by layer from top to bottom using picks and shovels. For harder, strongly weathered sandstone and moderately weathered sandstone, a water-jet drilling technique is employed.

[0115] The water-jet drilling method primarily involves drilling several holes along the inner edge of the pile diameter using a water-jet drilling rig. These holes are connected, and core samples are taken after drilling. Once all the drilled holes form a rectangle, the pile core separates from the pile wall, creating a free surface for the core. The remaining core rock is then segmented. A row of small holes is drilled into each segment, and steel wedges are inserted into these holes. The wedges are then hammered to compress the rock, causing it to fracture along the vertical surface and shear from the bottom, breaking it into several small pieces. These fragments are then lifted out of the holes using a winch and removed. This process of layered core drilling, fracturing, and rock fragment removal is repeated cyclically.

[0116] Water-based drilling process: (1) Erecting scaffolding The construction scaffolding is erected using ordinary steel pipe scaffolding. The four corners of the scaffolding are located outside the pile opening. After the scaffolding is erected, the winch and pulleys are fixed on the scaffolding, the power is connected, and it is adjusted to normal working condition.

[0117] (2) Core drilling with water-grinding drill The sidewall of the bored pile is inclined outward at a certain angle. This ensures that the starting point of the sleeve can be placed on the designed edge line of the bored pile after the drilling rig is in place during the next cycle, so as not to cause hole shrinkage. This measure will make the pile hole a segmented inverted body and ensure the cross-sectional dimensions of the hole.

[0118] (3) Inserting and striking the steel wedges to split the rock. Steel wedges are driven into holes drilled radially along the pile foundation using a hand drill. A sledgehammer is then used to strike the wedges, applying a horizontal impact force to the rock mass. Under this force, the rock is pulled apart along the vertical surface of the hammer, and horizontal shear fractures occur at the bottom. This process of splitting the rock mass continues until the entire core rock layer is fractured.

[0119] (4) Piling hole correction and construction of the next cycle Because the borehole wall of the pile foundation is serrated after core drilling with a water-jet drill, the rock serrations that encroach on the pile foundation space must be knocked away to ensure that the effective pile diameter is consistent with the design pile diameter. The design pile center is marked in the pile hole by using a locking pile protector, the deviation of the bottom of the pile foundation is checked and corrected in time, and the position for core drilling of the outer perimeter of the next cycle is marked, and the drilling pile construction of the next cycle begins.

[0120] S400, arm guard template installation.

[0121] Furthermore, the installation of the protective arm template includes: after drilling the hole, laying acrylic sheets around the protective arm. At this time, the acrylic sheets can play a quality protection role for the anchor pile, ensuring the flatness of the anchor pile and ensuring that there are no quality defects such as air bubbles, sand lines, and cracks in the pile body.

[0122] S500, wall protection concrete pouring.

[0123] Furthermore, the wall protection concrete pouring includes: when there is no water or the water volume in the hole is small, installing a concrete tremie pipe to the bottom of the hole, the bottom of the tremie pipe should not be more than the second safety distance from the bottom of the hole, and then starting to pour the pile core concrete.

[0124] Specifically, concrete pouring methods include: (1) After drilling, carefully clean the slag, and pour concrete after installing the reinforcing cage.

[0125] (2) The concrete is self-mixed concrete from the mixing plant.

[0126] (3) The concrete mixing plant shall strictly mix concrete in accordance with the designed mix proportion.

[0127] (4) Concrete transport access roads should be smooth. During transportation, it should be ensured that the concrete does not segregate, leak, bleed excessively, or suffer excessive slump loss. The concrete transported to the pouring site should still maintain uniformity and the specified slump.

[0128] (5) During concrete pouring, a tremie pipe is used to assist in material feeding, ensuring that the end of the tremie pipe is no more than 1m away from the concrete pouring surface to prevent coarse aggregate from separating from cement mortar and causing segregation. The concrete is compacted once every 0.3m of pouring using an immersion vibrator. During compaction, the vibrator should be inserted 10cm into the lower layer of concrete to strengthen the bond between the upper and lower layers and ensure the density of the pile core concrete.

[0129] (6) During the pouring process, the vibration points of the vibrator should be spaced 0.4–0.5 m apart, and the vibration time at each point should be 20–30 seconds. The degree of vibration should be limited to the point where the concrete surface no longer shows obvious settlement and no air bubbles overflow. Vibration should be carried out by professional personnel wearing safety ropes, with two people escorting them down into the hole from the hole opening.

[0130] (7) The pile core concrete must be poured continuously without leaving any construction joints. After the pile core concrete is poured, the exposed parts should be watered for curing within 24 hours.

[0131] (8) After the concrete is poured, a settlement observation mark is pre-embedded at the center of the top of the anchor pile to facilitate the observation of pile top displacement and settlement during construction and after completion.

[0132] Specifically, the process of pouring concrete under waterless conditions includes: If there is no water or a small amount of water in the borehole, a concrete tremie pipe should be used for pouring. After the pile hole and reinforcing cage have passed inspection, the concrete tremie pipe should be installed to the bottom of the hole in a timely manner, with the bottom of the tremie pipe no more than 2 meters from the bottom of the hole. Then, the core concrete should be poured. The concrete mix proportion should be strictly prepared according to the mix proportion approved by the supervisor.

[0133] The shunt tube has a diameter of 20cm, and each section is 1m long. The upper and lower sections are connected by lifting lugs, and the height between the bottom of the shunt tube and the bottom of the hole or the concrete surface is no more than 1m. The shunt tube is removed section by section as the concrete is poured.

[0134] The concrete for the pile body is centrally mixed at the batching plant and transported by concrete mixer trucks. A crane is used to assist in the pouring of the concrete, which is then fed into the well through a tremie pipe. Each layer of concrete must not exceed 30cm in height, and each layer is compacted until it reaches the top of the pile. The vibration method involves workers underground vibrating the concrete every 30cm. The tremie pipe is securely suspended in the middle with nylon ropes to prevent it from falling and injuring people.

[0135] Specifically, the process of pouring concrete under water conditions includes: (1) Before use, in addition to carefully inspecting its specifications, quality, and splicing structure, the guide pipe should undergo trial assembly and pressure test for water seepage. The test pressure should be 1.5 times the hydrostatic pressure at the bottom of the hole. The length of the guide pipe for the pressure test and water seepage test should meet the requirements for pouring the longest pile. The guide pipes should be numbered sequentially from bottom to top according to their segment lengths, and the assembly order of the guide pipes should be strictly maintained. Each group of guide pipes should not be mixed. The guide pipes are connected using a roller nut and sealed with rubber "O" rings to prevent water leakage. The length of the guide pipe should be determined according to the hole depth and the height of the working platform. Non-standard section guide pipes are recommended for the section from the bottom of the funnel to the top of the borehole.

[0136] (2) Before pouring concrete, the concrete tremie pipe and storage hopper should be moistened with water, then the baffle system should be installed and a water-tight plug should be set. After the storage hopper is full of concrete, the concrete pouring should begin. The amount of concrete poured in the first batch should be sufficient to meet the requirement that the initial embedment depth of the tremie pipe is not less than 1m and to fill the bottom height of the tremie pipe. During the pouring process, the embedment depth of the tremie pipe should be controlled between 2-6m. The mixed concrete should be transported to the pile foundation opening by a concrete truck and poured into the storage hopper. Then, the baffle should be opened to seal the bottom. The isolation bolts should be made of steel plates, which should be pulled by thin steel wire ropes and lifted by a crane. Concrete pouring should be carried out in a timely manner. If the time is too long, the sediment should be measured again. After the tremie pipe reaches a certain embedment depth, the tremie pipe should be disassembled quickly in stages, and the height of the concrete surface in the hole should be measured once before each lifting of the tremie pipe.

[0137] S600, final hole sealing.

[0138] In some embodiments, prior to the pouring of the retaining concrete, the process also includes: fabrication of the reinforcing cage, hoisting, and installation of the sonic logging tube.

[0139] Furthermore, the process of fabricating, hoisting, and installing the sonic logging pipes includes: Due to the diverse types of reinforcing bars used in rectangular manually excavated bored piles, external operations are not permitted. Each section of the reinforcing cage is fabricated according to the design dimensions and reinforcement specifications, and then tied and mechanically connected using sleeves inside the well. When dividing the reinforcing cage into sections, the number of joints at each section shall not exceed 50% of the total number. Mechanical sleeve connections are used for the reinforcing cages, with joints within a 35d range and not less than 50cm. During the reinforcing bar fabrication process, the spacing, length, specifications, and quantity of the reinforcing bars must meet the design requirements, and any deviations during fabrication must be controlled within the specified limits.

[0140] When installing sonic logging pipes in the reinforcing cage, the lower end of the pipe should be sealed, and the upper end sealed with a wooden plug to facilitate later testing. The sonic logging pipes are made of seamless steel pipe with an inner diameter of 50mm and a wall thickness of 3mm. Every 2m, the sonic logging pipe is welded to the main reinforcement with φ8 steel bars, extending 10cm-30cm above the design elevation of the pile top. The height of each pipe opening should be consistent, and one pipe is installed at each of the four corners of each pile. The sonic logging pipes are located inside the reinforcing cage. The pipes should be vertical, and bending in the middle is strictly prohibited, as it will affect subsequent testing. The lower end is sealed, and the upper end is sealed with a wooden plug. There should be no foreign objects inside the pipe, and the joints should be smooth and leak-proof. After the sonic logging pipes are installed, water can be injected to check for leaks at the joints. If leaks are found, the pipes should be replaced.

[0141] In some embodiments, pile foundation monitoring is also included after the final hole sealing.

[0142] Furthermore, pile foundation monitoring includes: (1) conducting pile quality testing according to design requirements. After the pile foundation concrete reaches the design strength, a non-destructive testing method (ultrasonic method) is used to test the pile body, determine the quality of the pile concrete, identify any defects, and determine the depth and thickness of the defects. If defects are found in the pile concrete, appropriate remedial measures or treatment methods should be taken and the issues addressed promptly.

[0143] (2) If abnormal conditions are encountered during construction and the quality of the piles may be lower than the required standards, the piles should be tested by core sampling according to the instructions of the supervisor or the owner in order to verify the quality of the pile foundation concrete.

[0144] (3) After the pile foundation testing is completed, the sonic logging tubes should be sealed in a timely manner.

[0145] In summary, the anchor piles in this embodiment employ intermittent excavation, using a combination of water-jet drilling and blasting. Weak vibration blasting should be used during construction, with strict control of explosive dosage. Large-scale blasting is prohibited. During excavation, manual labor is used in conjunction with an electric winch for soil removal. The bored pile construction follows a top-down sequence. Slope protection must be implemented before construction, followed by progressive excavation and protection until the pile top is reached, ensuring the excavated slope is in a safe protected state. For concrete poured under conditions of no water or where a small amount of water can be pumped out, the tremie pipe method is used.

[0146] During the construction of anchor piles, concrete interlocks and retaining walls should be used to protect soil layers and weathered and broken rock layers. The retaining wall joints should not be left at the rock layering, soil-rock boundary, or soil layer boundary. The interlocks and retaining walls should be constructed immediately after the pile well is excavated. The joints should not be located at the stratum boundary or slip bed to ensure construction safety.

[0147] Finally, it should be noted that the above embodiments are only used to illustrate the technical solutions of the present invention, and not to limit them; although the present invention has been described in detail with reference to the foregoing embodiments, those skilled in the art should understand that modifications can still be made to the technical solutions described in the foregoing embodiments, or equivalent substitutions can be made to some of the technical features; and these modifications or substitutions do not cause the essence of the corresponding technical solutions to deviate from the spirit and scope of the technical solutions of the embodiments of the present invention.

Claims

1. A method of constructing a highway guard anchor pile, characterized by, Comprise: Measurement loft; Installation of protective facilities construction; Excavation construction; the excavation construction comprises: For silty clay, coarse angular gravel soil, gravel soil and pebble stratum, artificial excavation; For weathered layer and medium weathered hard rock, machine crushing excavation; For hard and strong weathered sandstone and medium weathered sandstone, blasting excavation; Formwork installation; Formwork pouring; Final hole sealing.

2. The method of claim 1, wherein, The blasting excavation for hard and strong weathered sandstone and medium weathered sandstone comprises: When the hole depth enters the strong weathered sandstone layer, and the distance from the pile bottom elevation is outside the safety threshold range, the blasting method is used to excavate; Within the safety threshold range from the bottom elevation, the method of artificial everywhere chiseling is used to excavate to the position.

3. The method of claim 2, wherein, The blasting excavation for hard and strong weathered sandstone and medium weathered sandstone comprises: According to the blasting design, the hole arrangement and drilling operation are carried out, wherein the hole arrangement adopts the quincunx type hole arrangement; After charging and plugging are completed, network connection is carried out according to the blasting design, and the joints are wrapped with insulating tape; According to the protection range and protection measures in the blasting design, protection is carried out, and before blasting, the fuse is fixed at the hole opening, and the cannon is pressed with sandbags.

4. The method of claim 3, wherein, After the protection range and protection measures in the blasting design are carried out, the fuse is fixed at the hole opening, and the cannon is pressed with sandbags, then further comprising: The blasting is carried out by using the hole-by-hole millisecond initiation method.

5. The method of claim 3, wherein, After charging and plugging are completed, network connection is carried out according to the blasting design, and the joints are wrapped with insulating tape, comprising: For the parts with requirements for blasting vibration and blasting fly rock in the surrounding environment, the hole-by-hole initiation network is used.

6. The method of claim 2, wherein, The explosive is emulsion explosive.

7. A method of installing a highway barrier anchor post according to any one of claims 1 to 6, characterised in that, The formwork installation comprises: After the hole is formed, according to the exposed length of the anchor pile, the acrylic plate is laid on the anchor pile formwork.

8. The method of claim 7, wherein, The formwork pouring comprises: When there is no water or the water amount is small in the hole, the concrete string drum is installed to the hole bottom, the distance between the string drum bottom and the hole bottom should not exceed the second safety distance, and then the pile core concrete is poured.

9. The method of claim 8, wherein, Before the formwork pouring, further comprising: Steel reinforcement cage manufacturing, hoisting and acoustic pipe installation.

Images