WO2022001310A1

WO2022001310A1 - Method for passing through river channel and laying cable by using horizontal directional drilling technology

Info

Publication number: WO2022001310A1
Application number: PCT/CN2021/088858
Authority: WO
Inventors: 杨建伟; 姚自勇; 张智勇; 李毅东; 余红波; 何旭亮; 裴大威; 王绪湘; 连继业; 梁永全; 王崇康
Original assignee: 广东顺德电力设计院有限公司
Priority date: 2020-07-02
Filing date: 2021-04-22
Publication date: 2022-01-06
Also published as: CN112103852A; CN112103852B

Abstract

Disclosed are a method for passing through a river channel and laying a cable by using horizontal directional drilling technology. The steps of the method comprise: S1: calculating a first steel pipe top elevation and a second steel pipe top elevation according to a lowest navigable water level, a planned channel water depth, a riverbed sapping thickness, a riverbed bottom elevation and a pre-embedded depth, and selecting the smaller of the two top elevations as the minimum value of an actual steel pipe top elevation; S2: selecting steel pipes for cable laying and the number thereof, and MPP pipes built into the steel pipes and the number thereof, and determining a passing-through path of a horizontal directional drill according to the minimum value of the actual steel pipe top elevation, the radii of curvature of the steel pipes, a stratum through which the steel pipes pass, and a ground entry point and a ground exit point of the horizontal directional drill; S3: calculating, according to the passing-through path, the traction and lateral pressure during cable laying, and determining whether a construction requirement is met; and S4: forming a guide hole in a river channel by using the horizontal directional drill, pulling the steel pipes back, arranging the MPP pipes to pass through the steel pipes, and laying a cable. Precise parameter calculation is carried out, and the laying of a cable between transformer stations on two sides of a river channel is then completed by means of steel pipes passing through the river channel. The project cost is low, the construction period is short, and the implementation is simple.

Description

A method for crossing river channels and laying cables using horizontal directional drilling technology

technical field

The invention relates to the field of cable laying, and more particularly, to a method for traversing a river channel and laying cables using horizontal directional drilling technology.

Background technique

Horizontal directional drilling rig is a construction machine that lays various underground utilities (pipes, cables, etc.) without excavating the ground surface. It is widely used in flexible pipelines such as water supply, electricity, telecommunication, natural gas, gas, oil, etc. In the laying construction, it is suitable for sandy soil, clay, etc., the groundwater level is high and the pebble stratum is not suitable for most non-hard rock areas in my country. The working environment temperature is -15℃～+45℃. Horizontal directional drilling technology is a new construction technology that combines the directional drilling technology of the petroleum industry and the traditional pipeline construction method. It has the advantages of fast construction speed, high construction accuracy and low cost. It is widely used in water supply, Gas, electricity, telecommunication, natural gas, oil and other pipelines are being laid in construction projects. As a modern trenchless construction method, horizontal directional drilling is one of the three major trenchless technologies today, along with pipe jacking and shield tunneling. Horizontal directional drilling technology has the advantages of small environmental damage, short construction period, low comprehensive cost, and significant social benefits, and is widely used in the construction of underground pipelines.

In the cable laying project in the city, sometimes there are substations on both sides of the river, so the cables must be laid across the river. Laying cables in the river is called underwater laying. The trench excavation at the bottom is a long construction process and requires a lot of manpower and material resources.

SUMMARY OF THE INVENTION

The present invention aims to overcome at least one defect of the above-mentioned prior art, and provides a method for crossing a river channel and laying cables using horizontal directional drilling technology, which is used for rapid underwater cable laying, and can achieve short construction period and comprehensive cost. low effect.

The technical scheme provided by the present invention is:

A method for crossing a river channel and laying cables using horizontal directional drilling technology, the steps comprising:

S1: Calculate the top elevation of the first steel pipe according to the lowest navigable water level, the water depth of the planned channel, the undercut thickness of the river bed and the embedded depth; calculate the top elevation of the second steel pipe according to the bottom elevation of the river bed, the undercut thickness of the river bed and the embedded depth; the top elevation of the first steel pipe and the top elevation of the second steel pipe, and the minimum value between the two is selected as the minimum value of the actual steel pipe top elevation;

Before construction, it is necessary to determine various parameters for the implementation of horizontal directional drilling technology, as well as the parameters of steel pipes and MPP pipes used in laying cables, etc. before construction.

First, calculate the top elevation of the steel pipe when it is laid underwater. The top elevation is divided into the top elevation of the first steel pipe and the top elevation of the second steel pipe; the top elevation of the first steel pipe cable is calculated from the water depth of the planned channel, which is calculated from the minimum navigable water level, the water depth of the planned channel, The undercut thickness of the river bed and the preset burial depth are calculated; the top elevation of the second steel pipe is calculated from the maximum water depth of the project location, and is calculated from the bottom elevation of the river bed, the undercut thickness of the river bed and the preset safety coverage thickness required for cable burial.

Among them, the undercut thickness of the river bed refers to the vertical erosion and cutting effect of the flowing water on the river bed. When the amount of sediment in the upper reaches of the river is less than the water carrying capacity, the vertical erosion and cutting effect of the water flow is strong, and the elevation of the river bed gradually decreases. Therefore, considering the undercut thickness of the river bed, the top elevation for safe laying of steel pipes can be obtained more accurately. After calculating the two pipe top elevations, compare the two elevations and select the minimum value as the minimum actual pipe top elevation.

S2: Select the steel pipe for laying the cable and its quantity, and select the MPP pipe and its quantity set in the steel pipe according to the steel pipe; The actual horizontal traversing stratum, the radius of curvature of the steel pipe and the minimum value of the top elevation of the actual steel pipe, the entry point and the excavation point of the horizontal directional drilling, determine the crossing route of the steel pipe;

Step S2 is to determine the relevant parameters of the steel pipe and MPP pipe used in laying the cable, firstly select the steel pipe material and specification for laying the cable and the quantity of the steel pipe according to the needs of the cable laying, and then determine the steel pipe according to the situation of laying the cable. The number and specifications of MPP pipes set inside, MPP pipes are commonly used power pipes for directly laying cables, and steel pipes are pipes to protect MPP pipes. The entry point and the excavation point of the horizontal directional drilling are determined according to the location of the substations on both sides of the river and the geographical location of the two sides of the river.

Further combined with the on-site investigation of the river channel, the foundation soil that the steel pipe is expected to cross the river channel is divided into several engineering geological layers, and the several engineering geological layers are designated as the actual horizontal traversing strata for horizontal directional drilling. The radius of curvature of the steel pipe and the minimum value of the actual top elevation of the steel pipe are further determined according to the entry point and the excavation point of the horizontal directional drilling and the feasibility of comprehensively considering the construction. The location of the unearthed can determine the crossing route of the steel pipe in the river.

S3: Calculate the traction force and side pressure when the cable is laid according to the crossing route, and verify whether the cable laying meets the construction requirements according to the traction force and side pressure: if it is satisfied, go to step S4, if not, perform step again S1;

Determine the traction force and side pressure generated by the cable during the laying process according to the crossing route determined in step S2. It is necessary to verify whether the traction force and side pressure generated in the process of mechanically laying the cable are within the range that the cable can bear. , the next step can be performed; if it is outside the cable bearing range, it is necessary to re-adjust the crossing route, including adjusting the directional drilling, excavation point and excavation angle, etc., so that the traction force and lateral pressure of the cable can be kept within the cable bearing capacity. within the range.

S4: According to the crossing route, use the horizontal directional drill to form a pilot hole in the river channel and ream the pilot hole, and drag a number of the steel pipes back into the pilot hole after reaming, according to the The number of the MPP pipes in step S2 is to pass through the MPP pipes in the steel pipes; the cables are laid in the MPP pipes.

According to the crossing route, the horizontal directional drilling is officially used for construction under the river channel, forming a pilot hole and reaming the pilot hole, dragging several steel pipes back into the pilot hole after reaming and passing MPP pipes in each steel pipe, and then reaming the pilot holes. The pipeline setting for cable laying is completed, and finally only the cable needs to be laid in the pipeline to complete the cable laying across the river. The horizontal directional drilling technology is used to realize the crossing of the cable in the river. After accurate parameter calculation, the cable can be safely and stably laid in the steel pipe. The steel pipe is used to cross the river to complete the laying of the cable between the substations on both sides of the river. The project cost is low. , the construction period is short, and the implementation is difficult and easy.

Further, before the execution of step S4, a number of wells are respectively set at the entry point and the excavation point, and the number of the wells is the same as the number of the steel pipes; in step S4, "the cable is laid on the MPP pipe" "Medium", specifically: dividing the cable at the earth entry point into the same number of cable branches as the MPP pipes, and laying the cable branches on the MPP of the steel pipe through the well of the earth entry point in a trumpet-shaped dispersion manner In the pipe, the cable branch is connected to the cable at the excavation point through the MPP pipe from the work well at the excavation point in a horn-shaped bundle; one well at the excavation point and one at the excavation point. All wells only provide one cable branch to pass through, and only one cable branch is laid in one of the steel pipes.

Step S4 is to lay the cables. The cables to be laid are divided into several cable branches for laying, and only one cable branch is laid in each steel pipe. The cables at the soil entry point are divided into several cable branches. The distributed method is laid in the steel pipe through a well, and each cable branch is laid in the MPP pipe of a steel pipe through a well, and the cable branches do not share the same well and the same steel pipe; at the excavation point, the cable The branches are also flared to the cables at the excavation site. The trumpet-shaped dispersion and convergence design makes the connection between the steel pipe pipeline and the cable section smooth, and the cable arrangement is neat and orderly.

Further, in step S1, "calculate the elevation of the top of the first steel pipe according to the minimum navigable water level, the planned water depth of the waterway, the undercut thickness of the river bed and the preset buried depth", specifically: calculating the elevation of the top of the first steel pipe _{according to H 1 =hHdB,} Wherein, the H ₁ is the top elevation of the first steel pipe, the h is the minimum navigable water level, the H is the water depth of the planned waterway, the d is the undercut thickness of the river bed, and the B is the pre-planned water depth. Buried depth.

The minimum navigable water level refers to the minimum required navigable water level at which the vessel does not touch the bottom during navigation, and the planned channel water depth refers to the vertical distance from the water surface to the bottom within the channel range. In terms of local sections, it usually refers to the vertical distance from the water surface to the bottom of the shallowest part of the channel; the undercut thickness of the river bed refers to the vertical erosion and cutting effect of the flowing water on the river bed, and the amount of sediment from the upper reaches of the river is less than that of the river bed. When the sand force is high, the vertical erosion and cutting effect of the water flow is strong, so that the river bed elevation gradually decreases. Therefore, considering the undercut thickness of the river bed can more accurately obtain the top elevation of the cable for safe laying; the pre-buried depth refers to the preset depth according to the local regulations for laying cables under water, which is a preset value in the calculation.

Further, in step S1, "calculate the top elevation of the second steel pipe according to the bottom elevation of the river bed, the undercut thickness of the river bed and the preset safety cover thickness required for cable burial", specifically: calculating the second steel pipe according to H ₁ =h ₁ -dB steel top elevation, wherein said H ₁ is a top elevation of the second steel pipe, h ₁ is the bottom elevation of the bed, the bed d is the thickness of the cut, and B is the depth of said embedded. The bottom elevation of the riverbed refers to the vertical distance from the bottom of the riverbed to the water surface.

Further, the water depth of the planned waterway in step S1 is calculated according to H=T+ΔH, wherein, the H is the water depth of the planned waterway, and the T is the water depth of the ship or fleet taken according to the waterway conditions and transportation requirements. The draught or the draught when the load is reduced in the dry season, the ΔH is the margin for the bottoming safety of the ship determined according to the level of the fairway.

When calculating the water depth of the planned channel, a representative ship type should be selected according to the channel conditions and transportation requirements in the river channel, and the relevant draft depth should be measured according to the ship or fleet of the ship type, and the ship of the representative ship type should be determined when sailing. The safe and rich amount of the bottom, that is, the rich water depth.

Further, the included angle of the opening of the trumpet in step S4 ranges from 30° to 60°. The angle range can make the flared dispersion and convergence more convenient for the connection between the steel pipe and the cable, and the angle depends on the width and position of the steel pipe and MPP pipe.

Further, after selecting the steel pipe for laying the cable in step S2, before determining the actual horizontal crossing layer of the horizontal directional drilling in the river channel, calculate the tensile stress of the steel pipe determined in step S2 _{according to f t =1000F/A} ; Judging whether f _t < 0.9σ _s is established, if so, it means that the specification of the steel pipe meets the requirements, and step S2 can be continued; steel meet construction requirements selected; wherein the tensile stress f _t of the steel pipe, the force F is the maximum pull back the tube in the horizontal directional drilling when the pullback, the cross of the steel pipe a Cross-sectional area, the σ _s is the yield strength of the steel pipe under the specified specification.

Use the calculated tensile stress of the steel pipe to check whether the strength of the steel pipe meets the requirements of the tensile stress. If the strength of the steel pipe does not meet the requirements of the tensile stress, the selection of the steel pipe is wrong, and the applicable steel pipe needs to be re-selected.

Further, in step S3, "determine the traction force and side pressure when the cable is laid according to the crossing route, and verify whether the cable laying meets the construction requirements according to the traction force and side pressure", specifically: according to the path bending type The crossing route is divided into several sub-path sections, the traction force and lateral pressure of each sub-path section during cable laying are calculated, and whether the cable laying meets the construction requirements is verified according to the traction force and lateral pressure of each sub-path section.

Divide the crossing route from the well at the entry point to the well at the excavation point into several sub-path sections. The path bending types include horizontal bending traction and horizontal straight traction. The friction coefficient, the weight of the cable and the friction force of the cable reel are used to calculate the traction force and side pressure of several horizontal curved traction sub-path segments and several horizontal straight traction sub-path segments. The calculated traction force and side pressure of the sub-path segments should be If it is less than the carrying capacity of the cable, if it is greater than the carrying capacity of the cable, it does not meet the construction requirements, and the crossing route needs to be re-adjusted to keep the traction force and side pressure of the cable within the cable bearing range.

Further, the calculation process of the maximum pullback force F of the steel pipe during the pullback of the horizontal directional drilling is: according to

Calculate the maximum pullback force of the horizontal directional drilling, wherein the F is the maximum pullback force, the L is the length of the horizontal directional drilling path, the D is the inner diameter of the steel pipe, and the D ₁ is the outer diameter of the pipe of the steel pipe, the f _h is the friction coefficient between the pipe section of the steel pipe and the wall of the drilling hole, the γ _m is the weight of the drilling mud, and the t is the wall of the steel pipe Thickness, the γ _p is the pipe weight of the steel pipe, the ω _w is the weight of the steel pipe per unit length when buoyancy control is performed, and the K is the viscosity coefficient of the drilling mud.

Compared with the prior art, the beneficial effects of the present invention are:

(1) The present invention utilizes the horizontal directional drilling technology to realize the crossing of the cable in the river channel. After accurate parameter calculation, the cable can be safely and stably laid in the steel pipe. The implemented project cost is low, the construction period is short, and the implementation is difficult and easy;

(2) The present invention includes the undercut thickness of the river bed as a calculation parameter when calculating the most critical parameter for underwater laying of the river, that is, the elevation of the top of the steel pipe. When the amount is less than the sediment carrying capacity of the water flow, the vertical erosion and cutting effect of the water flow is strong, and the river bed elevation gradually decreases. Therefore, considering the thickness of the undercut of the river bed, the top elevation of the safe cable laying can be obtained more accurately.

(3) The cable branches enter from the entry point in a trumpet-shaped dispersion, and are connected to the cables at the excavation point in a trumpet-shaped convergence. The design of the flared dispersion and convergence makes the connection between the steel pipe pipeline and the cable section smooth, and the cable layout is neat and tidy. in order.

Description of drawings

FIG. 1 is a schematic structural diagram of a river channel and a steel pipe in Embodiment 1 of the present invention.

FIG. 2 is a schematic diagram of the connection between the well and the cable branch at the soil entry point in Embodiment 1 of the present invention.

FIG. 3 is a schematic structural diagram in which a traversing route is divided into several sub-path segments in Embodiment 1 of the present invention.

FIG. 4 is a schematic structural diagram of the MPP pipe inside the steel pipe in Example 1 of the present invention.

detailed description

The accompanying drawings of the present invention are only used for exemplary illustration, and should not be construed as limiting the present invention. In order to better illustrate the following embodiments, some parts of the drawings may be omitted, enlarged or reduced, which do not represent the size of the actual product; for those skilled in the art, some well-known structures and their descriptions in the drawings may be omitted. understandable.

Example 1

The present embodiment provides a method for traversing a river channel and laying cables by using a horizontal directional drilling technology, the steps comprising:

S11: According to the location of the substations on both sides of the river and the geographical location of both sides of the river, determine the entry point, the excavation point, the position of the horizontal directional drilling well and the minimum navigable water level;

S12: Calculate the top elevation of the first steel pipe according to the minimum navigable water level shown in Figure 1, the water depth of the planned channel, the undercut thickness of the river bed shown in Figure 1, and the preset buried depth;

S13: As shown in Figure 1, the top elevation of the second steel pipe is calculated according to the actual river bed bottom elevation shown in Figure 1, the river bed undercut thickness shown in Figure 1 and the preset safety coverage thickness required for cable burial;

S14: Compare the elevation of the top of the first steel pipe calculated in step S12 with the elevation of the top of the second steel pipe calculated in step S13, and select the minimum value between the two as the minimum value of the actual top elevation of the steel pipe, which is determined by the minimum value of the top elevation The lowest point of the pipeline as shown in Figure 1;

S21: Preliminarily select the steel pipe for laying the cable and determine the number of the steel pipe according to the needs of the cable laying, and select the MPP pipe and the number thereof arranged in the steel pipe according to the selected steel pipe;

S22: Combined with the on-site investigation of the river channel, divide the foundation soil where the steel pipe is expected to cross the river channel into several engineering geological layers, and set the several engineering geological layers as the actual horizontal crossing layers for horizontal directional drilling;

S23: According to the actual horizontal crossing stratum determined in S22, the radius of curvature of the steel pipe selected in step S21, the minimum elevation of the actual steel pipe top and the lowest point of the pipeline determined in step S12, the entry point and the excavation point determined in step S11, after comprehensive analysis The steel pipe pipeline shown in Figure 1 is obtained, through which the crossing route of the steel pipe when crossing the river can be obtained;

S3: Calculate the traction force and side pressure during cable laying according to the crossing route obtained in step S23, and verify whether the cable laying meets the construction requirements according to the calculated traction force and side pressure: if it is satisfied, then execute step S4, if not, then execute again Step S1, readjust the crossing route;

S41: according to the crossing route obtained in step S23, utilize horizontal directional drilling to form pilot holes in the river channel and carry out reaming to the pilot holes;

S42: Drag several steel pipes back in the guide holes formed in S41, and pass MPP pipes in the steel pipes according to the number of the MPP pipes in step S2; and lay cables in the MPP pipes.

As a preferred solution, before the execution of step S41, work wells are respectively set at the earth entry point and the excavation point, and the number of the work wells is the same as the number of steel pipes determined in step S21.

The specific execution process of "laying the cable in the MPP pipe" in S42 is:

As shown in Fig. 2, the cables at the soil entry point are divided into the same number of cable branches as the steel pipes. In this embodiment, the number of steel pipes is 4, so the number of cable branches is also 4, which is only an example Note, the actual number of cable branches and steel pipes will be determined according to the actual needs of cable laying.

After the cable is divided into 4 cable branches, the cable branches are laid in the steel pipe in a trumpet-shaped scattered way through several wells at the soil entry point, the cable branches are laid in the MPP pipe in the steel pipe, and the cable branches pass through the MPP pipe. The well at the point is connected to the cable at the excavation point in a horn-shaped bundle;

Only one cable branch is provided to pass through a well at an entry point and a well at an excavation point, and only one cable branch is laid in a steel pipe. The trumpet-shaped dispersion and convergence design makes the connection between the steel pipe pipeline and the cable section smooth, and the cable arrangement is neat and orderly. Wherein, as a preferred solution, the included angle of the opening of the trumpet is in the range of 30° to 60°. The angle range can make the horn-shaped dispersion and convergence more convenient for the connection between the steel pipe and the cable. The actual angle also depends on the width and position of the steel pipe and the MPP pipe.

As a preferred solution, the specific calculation process of step S12 is:

Calculate the elevation of the top of the first steel pipe according to H ₁ _{=hHdB, wherein the H 1} is the elevation of the top of the first steel pipe, the h is the minimum navigable water level shown in FIG. 1 , the H is the water depth of the planned channel, The d is the undercut thickness of the river bed shown in FIG. 1 , and the B is the embedded depth. Among them, as a preferred solution, the calculation method of the planned water depth H is: according to H=T+ΔH, the planned water depth is obtained, wherein the H is the planned water depth, and the T is determined according to the channel conditions and transportation requirements. Take the draught of the ship or fleet or the draught when the load is reduced in the dry season, and the ΔH is the margin for the bottoming safety of the ship determined according to the level of the channel.

As a preferred solution, the specific calculation process of step S13 is:

Calculate the elevation of the top of the second steel pipe according to H ₁ =h ₁ _{-dB, wherein the H 1} is the elevation of the top of the first steel pipe, the h ₁ is the bottom elevation of the river bed shown in FIG. The undercut thickness of the river bed shown, the B is the embedded depth. The bottom elevation of the riverbed refers to the vertical distance from the bottom of the riverbed to the water surface.

As a preferred solution, after the steel pipe for laying the cable is selected in step S21, the following steps should also be performed before determining the actual horizontal traversing stratum of the horizontal directional drilling in the river channel:

The tensile stress of the steel pipe f _t = 1000F / A calculation determined in step S21; Analyzing f _t <0.9σ _s is satisfied, such as the establishment, it indicates that the size of the steel pipe to meet the requirements, can proceed to step S22; if not set up, Then it indicates that the specifications of the steel pipe do not meet the requirements, and the steel pipe needs to be re-selected until the selected steel pipe meets the construction requirements; wherein the f _t is the tensile stress of the steel pipe, and the F is the horizontal directional drilling back of the steel pipe. The maximum pullback force when dragging, the A is the cross-sectional area of the steel pipe, and the σ _s is the yield strength of the steel pipe under the specification.

As a preferred solution, the calculation process of the maximum pullback force F of the above-mentioned steel pipe when the horizontal directional drilling is pulled back is as follows:

Calculate the maximum pullback force of the horizontal directional drilling, wherein the F is the maximum pullback force, the L is the length of the horizontal directional drilling path, the D is the inner diameter of the steel pipe, and the D ₁ is the outer diameter of the pipe of the steel pipe, the f _h is the friction coefficient between the pipe section of the steel pipe and the wall of the drilling hole, the γ _m is the weight of the drilling mud, and the t is the wall of the steel pipe Thickness, the γ _p is the pipe weight of the steel pipe; the ω _w is the weight of the steel pipe per unit length when buoyancy control is performed, and the K is the viscosity coefficient of the drilling mud.

As a preferred solution, the specific execution process of step S3 is as follows: according to the type of path bending, the crossing route is divided into several sub-path segments, the traction force and side pressure of each sub-path segment during cable laying are calculated, and the traction force of each sub-path segment is calculated according to the traction force of each sub-path segment. and side pressure to verify whether the cable laying meets the construction requirements.

As shown in Figure 3, the crossing route can be divided into four sub-path segments AB, BCD, DE and EF. The traction force and lateral pressure of the four sub-path segments during cable laying are calculated respectively. The specific calculation process is as follows:

The bending type of section AB is horizontal linear traction (roller), which does not generate side pressure. The calculation formula of _{its traction force T 1} _{is T 1} =fW+μWL ₁ , f is the friction force of the cable reel, W is the cable weight, μ is the roller The friction coefficient of the pipe section, L ₁ is the length of the AB section.

Type of segment BCD curved horizontal straight line of traction (wheel), no side pressure, the traction force T ₂ is calculated as _{_{_{T 2 = T 1 + μWL 2}}} , L 2 is the length of segment BCD.

The bending type of the DE section is horizontal bending traction (roller), the calculation formula of _{its traction force T 3} _{is T 3} =T ₂ e ^μθ , θ = 10° (that is, 10 rollers), and the calculation formula of its lateral pressure P is

Bending types of horizontal line segment EF traction (wheel), no side pressure, the traction force T ₄ is calculated _{_{_{T 4 = T 3 + μWL 4}}} , L 4 is the length of the segment EF.

After calculation _{, compare T 1} to T ₄ with the allowable value of cable traction force, and compare P with the allowable value of pressure on each roller side to judge whether the cable laying meets the construction requirements.

Divide the crossing route from the well at the entry point to the well at the excavation point into several sub-path sections. The path bending types include horizontal bending traction and horizontal straight traction. The friction coefficient, the weight of the cable and the friction force of the cable reel are used to calculate the traction force and side pressure of several horizontal curved traction sub-path segments and several horizontal straight traction sub-path segments. The calculated traction force and side pressure of the sub-path segments are both It should be less than the carrying capacity of the cable. If it is greater than the carrying capacity of the cable, it does not meet the construction requirements. It is necessary to re-adjust the crossing route to keep the traction force and side pressure of the cable within the cable bearing range.

As a preferred solution, the specific execution process of step S41 is:

S411: Release the drilling ground control line and equipment placement line according to the construction plan and the crossing route, and ensure that the center line of the drilling rig is in a straight line with the excavation point and the excavation point. The measurement points are determined on the site ground every 50 meters, and the guiding depth of each point is determined according to the design of the guiding trajectory. The engineering pipelines are buried at the bottom of the river bed to ensure at least a certain laying depth, so as to avoid mud emerging from the ground and the river bed during the construction process.

S412: Leveling the drilling site, leveling and compacting the requisitioned open space with excavators, and paving the surface with patterned steel plates to ensure sufficient bearing capacity.

S413: Prepare mud materials, use bentonite, positive gel, ammonium salt, starch and other polymer mud additives, industrial sodium carbonate (soda ash), extract the river water to test the pH value, add soda ash to the pH value of 8 to 9 before use . The use of each material should be carried out according to the construction plan, and it should be equipped and supplied in a planned and rhythmic manner.

S414: Calibrate the direction control parameters according to the operating procedures, and require careful measurement and comparison of as many parameters as possible, so as to determine the best parameters, and make a guide record.

S415: Before starting the construction, the water quality in the creek should be tested, and its pH value, hardness, impurity content, etc. should be measured. According to the operation requirements and geological conditions, the preparation plan is set up, the correct mixing sequence is determined, and the mud that meets the requirements is prepared according to different geological conditions. .

S416: After the drilling rig support and ground anchors are installed and fixed, the drilling rig is installed in place. After the screw drill tool and the roller cone bit are installed, the calibration of the guide instrument and the guide launch rod should be carried out. After each system runs normally, test run, and check the operation of each part after drilling 1-2 drill pipes, especially the parameters such as the torque, thrust, and pressure of the mud pump of the drilling rig.

S417: Select a suitable pilot bit according to the geological report, and drill the pilot hole according to the design drawing and the design drawing of the pilot trajectory. The drilling deviation meets the design requirements: the deviation between the actual curve of the pilot hole and the designed crossing route is not more than 1%, and the lateral allowable deviation ±3m; upper and lower allowable deviation +1m-2m; allowable lateral deviation of excavation point ±3m; longitudinal allowable deviation +9m-3m. Direction control is very important to the traversing accuracy and the success of the project. Before drilling, carefully analyze the geological data to determine the direction control plan and trajectory. When drilling the pilot hole, the hole formation should be analyzed according to the geological data and instrument parameters at any time.

S418: Determine the reaming level to be used according to the traversing stratum and equipment performance. In this embodiment, the reaming construction adopts four-level reaming, and the first-level reaming is installed on the

Rock reamer, optional for second stage

Rock type reamer, optional for the third stage

Rock type reamer, optional for the fourth stage

Rock reamer.

The specific execution process of step S42 is as follows: after clearing the pilot hole formed in step S41, after detecting that various parameters such as the torque and tension of the steel pipe meet the requirements of pipeline pulling back, pull back several steel pipes, according to the MPP of step S2. The number of pipes passes through the MPP pipes in the steel pipes; the cables are laid in the MPP pipes.

As a preferred solution, the steel pipe in this embodiment is a DN828×14 spiral steel pipe, and the steel pipe material is Q235B. As shown in FIG.

Obviously, the above-mentioned embodiments of the present invention are only examples for clearly illustrating the technical solutions of the present invention, and are not intended to limit the specific embodiments of the present invention. Any modifications, equivalent replacements and improvements made within the spirit and principle of the claims of the present invention shall be included within the protection scope of the claims of the present invention.

Claims

A method for crossing a river channel and laying cables using horizontal directional drilling technology, characterized in that the steps include:

S1: Calculate the top elevation of the first steel pipe according to the lowest navigable water level, the water depth of the planned channel, the undercut thickness of the river bed and the embedded depth; calculate the top elevation of the second steel pipe according to the bottom elevation of the river bed, the undercut thickness of the river bed and the embedded depth; the top elevation of the first steel pipe and the top elevation of the second steel pipe, and the minimum value between the two is selected as the minimum value of the actual steel pipe top elevation;

S2: Select the steel pipe for laying the cable and the quantity thereof, and select the MPP pipe and the quantity set in the steel pipe according to the steel pipe; The actual horizontal traversing stratum, the radius of curvature of the steel pipe and the minimum value of the top elevation of the actual steel pipe, the entry point and the excavation point of the horizontal directional drilling, determine the crossing route of the steel pipe;

S3: Calculate the traction force and side pressure when the cable is laid according to the crossing route, and verify whether the cable laying meets the construction requirements according to the traction force and side pressure: if it is satisfied, go to step S4, if not, perform step again S1;

S4: According to the crossing route, use the horizontal directional drill to form a pilot hole in the river channel and ream the pilot hole, and drag a number of the steel pipes back into the pilot hole after reaming, according to the The number of the MPP pipes in step S2 is to pass through the MPP pipes in the steel pipes; the cables are laid in the MPP pipes.
The method for crossing a river channel and laying cables using horizontal directional drilling technology according to claim 1, characterized in that, before step S4 is performed, several wells are respectively set at the earth entry point and the excavation point, and the number of the wells is the same as the number of said steel pipes;

"Laying the cable in the MPP pipe" in step S4 is specifically: dividing the cable at the soil entry point into the same number of cable branches as the steel pipes, and passing the cable branches in a trumpet-shaped dispersion manner. The well at the excavation point is laid in the MPP pipe of the steel pipe, and the cable branch is connected to the cable at the excavation point through the MPP pipe from the work well at the excavation point in a flared manner; a Only one cable branch is provided to pass through the well at the entry point and one well at the excavation point, and only one cable branch is laid in one of the steel pipes.
The method for crossing a river channel and laying cables using horizontal directional drilling technology according to claim 1, characterized in that in step S1, "calculate the first Elevation of the top of the steel pipe”, specifically: calculate the elevation of the top of the first steel pipe according to H 1 =hHdB, where the H 1 is the elevation of the top of the first steel pipe, the h is the minimum navigable water level, and the H is the The water depth of the planned channel, the d is the undercut thickness of the river bed, and the B is the pre-buried depth.
The method for crossing a river channel and laying cables using horizontal directional drilling technology according to claim 1, characterized in that, in step S1 "calculate the top elevation of the second steel pipe according to the bottom elevation of the river bed, the undercut thickness of the river bed and the pre-embedded depth" , specifically: calculate the elevation of the top of the second steel pipe according to H 1 =h 1 -dB, where the H 1 is the elevation of the top of the second steel pipe, the h 1 is the elevation of the bottom of the river bed, and the d is the The undercut thickness of the river bed, and the B is the embedded depth.
The method for crossing a river channel and laying cables using horizontal directional drilling technology according to claim 3, wherein the water depth of the planned channel in step S1 is calculated according to H=T+ΔH, wherein the H is the The water depth of the planned channel, the T is the draught of the ship or fleet taken according to the channel conditions and transportation requirements or the draught when the load is reduced in the dry season, and the ΔH is the safety bottom of the ship determined according to the channel grade. wealth.
The method for crossing a river channel and laying cables using horizontal directional drilling technology according to claim 2, wherein the included angle of the opening of the trumpet is in the range of 30° to 60°.
The method for crossing a river channel and laying cables using horizontal directional drilling technology according to claim 1, characterized in that, after selecting the steel pipe for laying the cable in step S2, after determining the actual horizontal directional drilling in the river channel before the level crossing formation, the steel pipe according to the tensile stress f t = 1000F / a calculation determined in step S2; Analyzing f t <0.9σ s is satisfied, such as the establishment, it indicates that the steel meet the construction requirements, may continue to step S2 ; If it is not established, it means that the steel pipe does not meet the construction requirements, and the steel pipe needs to be re-selected until the selected steel pipe meets the construction requirements;

Wherein the f t is the tensile stress of the selected steel pipe, the F is the maximum pullback force of the steel pipe when the horizontal directional drilling is pulled back, and the A is the cross-sectional area of the selected steel pipe , the σ s is the yield strength of the selected steel pipe.
The method for crossing a river channel and laying cables using horizontal directional drilling technology according to claim 1, characterized in that in step S3 "determine the traction force and lateral pressure when laying the cable according to the crossing route, according to the Traction force and side pressure to verify whether the cable laying meets the construction requirements”, specifically: dividing the crossing route into several sub-path segments according to the cable traction type, calculating the traction force and side pressure of each sub-path segment during cable laying, Verify whether the cable laying meets the construction requirements according to the traction force and lateral pressure of each of the sub-path segments.
The method for crossing a river channel and laying cables using horizontal directional drilling technology according to claim 7, wherein the calculation process of the maximum pulling force F of the steel pipe when the horizontal directional drilling is pulled back is: according to

Calculate the maximum pullback force of the horizontal directional drilling, wherein the F is the maximum pullback force, the L is the length of the horizontal directional drilling path, the D is the inner diameter of the steel pipe, and the D 1 is the outer diameter of the pipe of the steel pipe, the f h is the friction coefficient between the pipe section of the steel pipe and the wall of the drilling hole, the γ m is the weight of the drilling mud, and the t is the wall of the steel pipe Thickness, the γ p is the pipe weight of the steel pipe, the ω w is the weight of the steel pipe per unit length when buoyancy control is performed, and the K is the viscosity coefficient of the drilling mud.