Non-excavation construction method:
1 directional pipe method construction process
Geological survey→crossing curve design→measuring magnetic azimuth→drilling position→drilling guide hole→reaming→returning→environmental protection→landform restoration
2 working principle of guiding pipe method
The working principle of the horizontal directional drilling rig is: during construction, according to the designed drilling trajectory (generally curved), a rig that can be drilled from the surface is used to drill an approximately horizontal guiding hole, and then the large diameter is changed after guiding the drill bit. The diameter of the reaming drill bit and the working pipe to be laid with a diameter smaller than that of the reaming drill bit, and then reverse reaming, while pulling the pipeline to be laid back into the borehole, when all the drill rods are towed back, the pipe laying work is also It's finished. According to the geological conditions, this project adopts graded reaming, which is divided into two levels of reaming, and then the method of towed the pipeline to carry out the construction.
3 equipment in place, installation, commissioning
Before the rig is in place, level the machine construction site (20m × 30m) to ensure the passage of equipment and entry and exit. The equipment and material storage site shall be no more than 15cm above the natural ground, flattened and crushed, and provided with a side groove of not less than 0.3m×0.3m. After the axis is hit, the rig is accurately placed according to the actual situation of the site and the angle of the site. After the drilling equipment, mud equipment and solid control equipment are installed, commission, check and test the equipment to ensure the safe operation of the equipment. After the installation of the steering device is completed, it is debugged to ensure the accuracy of the guiding hole. The mud storage and transportation pit (2m×4m×2m) and the mud storage and transportation pit at the unearthed end (2m×3m×2m). The excess mud is collected and transported by the suction truck. Pulp storage and transportation pit (2m × 4m × 2m) and mud storage and transport pit at the end of the earth (2m × 3m × 2m). The excess mud is collected and transported by the suction truck.
4 drill guide hole
The geological conditions of the crossing section of the crossing project are temporarily considered according to the type II soil, and the guiding hole trajectory curve is selected and designed according to the ground conditions. The key to the success of the drill guide hole is how to prevent the problem of landslide. Therefore, when drilling the guide hole, a reasonable mud ratio scheme is formulated according to the geological structure, and different mud formulas are selected under different geological conditions. In the project, it is necessary to add appropriate amount of macromolecular polymer and some multifunctional treatment agents to increase the viscosity of the mud and reduce the water loss of the mud, so that the performance is controlled at a density of 1.02 to 1.05 g/cm. Left and right, viscosity 45 ~ 55s, water loss 10mL, in order to better protect the pore wall, improve the suspension capacity of the mud in the hole. Add an appropriate amount of lubricant to the mud used in the inclined section to reduce the friction coefficient of the hole wall, so that the drill can be prevented from sticking.
In order to ensure the smooth progress of pre-expansion and back-drag work, it is required that the inclined section should be drilled in strict accordance with the design curve when drilling the guide hole. After the alignment of the axis and the rig is in place, the drilling can be started after the inspection is correct. After the probe is loaded into the probe box, the pilot drill bit is connected to the drill pipe after calibration and calibration. Rotate the drill pipe to test whether the probe transmits the signal normally. After the rotary drill is 2m, the traverse can be started according to the design trajectory. The steering device should adopt a cable steering system to improve the accuracy of the drilling. After the pilot hole is completed, the pre-reaming can be performed.
5 pre-reaming and grinding holes
a. Pre-reaming hole is pre-reamed by an FDP-30 type guiding drill, and the mud is drilled while expanding the hole, and the reaming level is gradually increased according to the rotating pressure and the pulling back pressure. The pre-reaming hole is pre-expanded by a directional drilling machine, and the mud is drilled while expanding the hole, and the reaming level is gradually increased depending on the rotating pressure and the pulling back pressure.
b. The number of holes to be reamed depends on the slewing pressure of the rig and the back pressure. The reaming level is as follows:
Use a φ320mm spiral reaming drill to expand it once.
Use a φ450mm spiral reaming drill to expand it once.
c. Prepare the mud circulation system before reaming. The working performance of the mud system supported by the FDP-30 pilot drilling rig is 5m3 per hour. The maximum circulation flow per mud day of the mud pump is 120m3. Excavate a mud pit at the entrance point and the excavation point, and equip with special equipment for clearing mud. Ensure the cleanliness of the construction site and achieve civilized construction.
6 tow tube
a. The towing pipe adopts a special returning device, and at the same time, the method of rotating and pulling back while using the mud is used. Thereby ensuring that the steel pipe anti-corrosion layer is not damaged.
b. The rotary transfer case adopts a special structure.
c. The connection between the centralizer and the working tube should be firm, and the connection between the working tube and the puller should be firm, safe, and sealed, and it should be reliable.
d. Use small-weight and high-viscosity mud, add mud treatment agent and pipe hole lubricant suitable for geological structure to reduce the resistance during dragging and reduce the load of the drilling machine.
e. Before the φ273×9 steel pipe is towed back, verify whether there is sufficient mud in the hole after reaming, so as to play back the wall to lubricate the wall.
f. After confirming the welding and anti-corrosion of the steel pipe, connect the steel pipe to the human end and the back to the tractor, and check whether all the towing systems (including equipment and process guarantee measures) are in the best condition.
g. Before the towing, under the φ273×9 steel pipe to be pulled back, place one roller at intervals of 20m and cooperate with the crane to prevent the outer wall of the steel pipe from being scratched in the dragging.
h. After the start of the dragging, it is necessary to make a smooth and uniform speed (can not stay in the dragging), and the speed is controlled at 0.08m/s. The operator will observe the change of the back pressure at the moment and report it in time to take necessary measures to make the steel pipe smoothly return.
i. When the pipe is towed, most of the mud will be recycled. It is necessary to dig two pits for temporary storage, and one for the mud to pour a pit for purification.
7 restoration of topography
After the work tube is finished, the site is cleaned and the construction equipment used is removed to restore the topography of the site.
The construction process diagram is shown in Figure 1.
The successful completion of the project has created the history of the largest pipeline gas project in the history of Zhongshan City, which will cross the river by directional drilling and non-excavation. It will enable urban and port town residents and industrial and commercial enterprises north of the Shijie River to use safe and clean. Convenient and continuous supply of natural gas from Hong Kong to promote the rapid economic development of the region, improve people's living standards, and lay the foundation for the arrival of natural gas next year.
3 Conclusion
The above-mentioned non-excavation technology not only reduces road excavation, reduces construction costs, but also solves some problems that cannot be constructed in traditional excavation, and when repairing old pipelines and installations with high difficulty; in West-East Gas Transmission, Guangdong LNG Large-scale pipeline network laying in the project; natural gas is widely used as a clean and environmentally friendly energy source, so that it can be used in natural gas replacement projects; to ensure that the supply of gas to customers is not severely interrupted, and when installing zone regulating valves and pipes; After the completion of the pipe network, if you need to update the old gas pipeline, it has a considerable advantage. The non-excavation technology replaces the civil construction (the trenching method), which not only advances the gas construction technology, but also reflects the rapid development of construction technology and technological modernization.
Bazhou Lutong Engineering Co., Ltd.: http://
Survival Pocket Knife,Tactical Survival Knife,Stainless Steel Survival Knife,Survival Knife
YangJiang Junxiong Trading & Industry Company Co.,Ltd , http://www.cn-sundo.com