CN111577975A

CN111577975A - Tamping equipment for reducing resistance of pipe wall of tamping pipe and tamping construction process thereof

Info

Publication number: CN111577975A
Application number: CN202010451406.7A
Authority: CN
Inventors: 邱德璟; 张�杰
Original assignee: Sichuan Petroleum Construction Engineering Co Ltd
Current assignee: Sichuan Petroleum Construction Engineering Co Ltd
Priority date: 2020-05-25
Filing date: 2020-05-25
Publication date: 2020-08-25
Anticipated expiration: 2040-05-25
Also published as: CN111577975B

Abstract

The invention provides a tamping device for reducing the resistance of the pipe wall of a tamping pipe and a penetrating tamping process thereof, wherein the tamping device for reducing the resistance of the pipe wall of the tamping pipe comprises a cutting ring, a steel sleeve, a grouting resistance-reducing component, a tamping hammer body and a track, wherein the track is fixedly arranged on the ground so that the steel sleeve can be tamped in a cut stratum along a preset direction on the track; the cutting ring is fixedly arranged at the front end of the steel sleeve, a groove for cutting a soil body is arranged at one end of the cutting ring, which is not connected with the steel sleeve, and the diameter of the cutting ring is larger than that of the steel sleeve so as to form an annulus between the wall of the steel sleeve and a cut stratum; the rammer is connected with the other end of the steel sleeve and can apply ramming force to the steel sleeve; the grouting drag reduction component is arranged in the annular space on the outer wall of the steel sleeve and can pump the slurry into the annular space so as to reduce the frictional resistance between the outer wall of the steel sleeve and the ground to be cut. The invention has the advantages of greatly reducing the resistance in the pipe tamping process, reducing the loss of tamping force and the like.

Description

Tamping equipment for reducing resistance of pipe wall of tamping pipe and tamping construction process thereof

Technical Field

The invention relates to the technical field of shale reservoir development, in particular to tamping equipment for reducing resistance of a pipe wall of a tamping pipe and a tamping construction process thereof.

Background

The pipe ramming is a technology for directly ramming a steel pipe to be paved into a stratum along a designed route by adopting a pipe ramming hammer to realize trenchless pipe paving. The working principle is that the larger impact force generated by the pipe rammer driven by compressed air directly acts on the rear end of the steel pipe, and the steel pipe integrally overcomes the friction force and the shearing resistance between the soil layer and the pipe body and forcibly cuts into the soil body. In the crossing construction, the method is a practical and effective direct pipe laying method process, and plays an important role in the aspects of protecting ground structures, isolating cobble layers to assist in hole forming, preventing slurry leakage and slurry outflow of soft strata and the like.

The traditional pipe ramming process main body equipment comprises an air compressor, a hammer body and a pipe body, wherein the pipe body is hammered by a large impact force which is provided by the air compressor in a simple process, the stratum resistance is forcibly overcome, and the pipe body is enabled to move forwards. Because the rammer single impact action time is extremely short, according to the momentum theorem F.t ═ delta mv, the effective energy that the body obtained is lower, and along with the increase of ramming pipe length, the loss of ramming power on the way of body also can increase gradually, and the sleeve pipe front end is difficult to obtain effectual propulsive energy, often can cause the circumstances that the rammer pipe later stage is not enough to produce.

If the tamping force is increased, in order to prevent the yield deformation of the pipe, the requirements on the properties of the pipe body, such as material quality, wall thickness and the like, are higher, and meanwhile, the quality of a welded junction is also greatly hidden danger due to the overlarge tamping force.

The traditional tamping pipe has extremely low utilization efficiency of the output tamping force, most of the tamping force is used for overcoming the resistance of the pipe wall to do work, and the effective tamping force actually loaded at the front end is lower. Therefore, a novel pipe ramming process technology needs to be researched, the defects of the traditional process technology are overcome, and the situation of transition dependence on the performance of the rammer and the material of the pipe is reduced. On the premise that the output energy of the rammer is limited, the resistance of the rammer pipe is greatly reduced by increasing the resistance-reducing lubricating measures, so that the aim of increasing the maximum ramming distance of the rammer pipe is fulfilled. Meanwhile, the equipment consumption and the pipe purchasing cost are reduced.

Disclosure of Invention

The present invention aims to address at least one of the above-mentioned deficiencies of the prior art. For example, it is an object of the present invention to provide a tamping apparatus that reduces the resistance of the wall of the tamping tube and increases the maximum tamping distance of the tamping tube.

In order to achieve the above object, an aspect of the present invention provides a tamping apparatus for reducing the resistance of the wall of a tamping tube.

The tamping equipment comprises a cutting ring, a steel sleeve, a grouting drag reduction component, a tamping hammer body and a track, wherein the track is fixedly arranged on the ground so that the steel sleeve can be tamped in the cut stratum along a preset direction on the track; the cutting ring is fixedly arranged at the front end of the steel sleeve, a groove for cutting a soil body is arranged at one end of the cutting ring, which is not connected with the steel sleeve, and the diameter of the cutting ring is larger than that of the steel sleeve, so that an annulus is formed between the wall of the steel sleeve and a cut stratum; the rammer is connected with the other end of the steel sleeve and can apply ramming force to the steel sleeve; the grouting drag reduction component is arranged in the annular space on the outer wall of the steel sleeve and can pump the slurry into the annular space so as to reduce the frictional resistance between the outer wall of the steel sleeve and the ground to be cut.

In an exemplary embodiment of an aspect of the present invention, the ramming apparatus may further include an air compressor connected to the ram through a high pressure pipe to drive the ram to generate the ramming force.

In an exemplary embodiment of an aspect of the present invention, the grouting drag reduction component may include a first grouting straight pipe, a second grouting straight pipe, a connecting bent pipe, and a three-way connection valve, wherein the first grouting straight pipe, the second grouting straight pipe, and the connecting bent pipe are respectively provided with an opening for injecting slurry into the annular space, the first grouting straight pipe and the second grouting straight pipe are respectively arranged on the outer wall of the steel casing in the axial direction of the steel casing, the connecting bent pipe is arranged on the outer wall of the steel casing in the circumferential direction of the steel casing and two ends of the connecting bent pipe are respectively connected with the first grouting straight pipe and the second grouting straight pipe, and the three-way connection valve is respectively connected with one ends of the first grouting straight pipe and the second grouting straight pipe which are not connected with the connecting bent pipe.

In an exemplary embodiment of an aspect of the invention, the openings on the first straight grouting pipe, the second straight grouting pipe and the connecting elbow may have different orientations.

In an exemplary embodiment of an aspect of the present invention, the first straight grouting pipe and the second straight grouting pipe may be axially disposed at ten and two points on an outer wall of the steel casing, and the first straight grouting pipe and the second straight grouting pipe may have latches welded at intervals to fix the first straight grouting pipe and the second straight grouting pipe.

In an exemplary embodiment of an aspect of the invention, the diameter of the elbow is less than the wall thickness of the cutting ring.

In an exemplary embodiment of an aspect of the invention, the ramming apparatus may further comprise a mud pump connected to the three-way junction valve via a high pressure hose to deliver mud to the slip reduction unit.

In an exemplary embodiment of an aspect of the present invention, the wall thickness of the cutting ring may be 1 to 2 times that of the steel casing, the length of the cutting ring may be 20 to 50cm, the length of a portion of the cutting ring not overlapped with the steel casing may be 1 to 5cm, and the cutting ring and the steel casing may be connected by full-length welding.

In an exemplary embodiment of an aspect of the present invention, the material strength of the cutting ring is not lower than that of the steel casing, the inner groove is obliquely formed on one side, and the groove angle may be 30 to 40 °.

The invention also aims to provide a tamping construction process which can reduce the resistance of the pipe wall of the tamping pipe in the tamping pipe construction process, improve the maximum tamping distance of the tamping pipe and save the construction period.

Another aspect of the invention provides a tamping construction process for reducing the resistance of a long-distance tamping pipe wall. The ramming construction process aims at the cohesive soil stratum with plasticity index Ip being more than 10 and does not contain silt and mucky soil, the ramming construction process can be realized by the ramming equipment for reducing the resistance of the pipe wall of the ramming pipe, and the ramming construction process comprises the following steps:

manufacturing and installing tamping equipment for reducing the resistance of the pipe wall of the tamping pipe;

and (3) grouting for a period of time before starting tamping, continuously grouting in the tamping process, recording the tamping force and the change of the tamping speed, and adjusting the tamping force according to the change of the tamping speed to keep the tamping speed within the range of 0.005-0.02 m/s until tamping is finished.

Compared with the prior art, the beneficial effects of the invention can comprise at least one of the following:

(1) the frictional resistance of the outer wall of the pipe is greatly reduced, the maximum distance for tamping the sleeve is increased, and the construction period for tamping the pipe is greatly saved;

(2) before the rammer is started, slurry is poured into the annular space in advance, and the slurry is poured in the whole process in different time periods in the ramming process, so that a mud cake is formed in the annular space, the friction coefficient is reduced, and meanwhile, the wall protection and hole stabilization effects are achieved to a certain extent;

(3) the transition dependence on the performance of the rammer and the material of the pipe is reduced, and the resistance of the rammer pipe is greatly reduced by increasing the resistance-reducing lubricating measures on the premise that the output energy of the rammer is limited so as to achieve the purpose of increasing the maximum ramming distance of the rammer pipe and simultaneously reduce the equipment consumption and the pipe purchasing cost.

Drawings

FIG. 1 shows a schematic structural view of a tamping apparatus for reducing the resistance of the wall of a tamping tube, according to an exemplary embodiment of the present invention;

FIG. 2 shows a schematic cross-sectional view of the steel casing of FIG. 1 with a cutting ring installed;

FIG. 3 shows a schematic plan view of the piping in the grout drag reduction part of FIG. 1;

fig. 4 shows a schematic cross-sectional view of the piping in the grout drag reduction unit of fig. 1.

The reference numerals are explained below:

1-cutting ring, 2-steel sleeve, 3-grouting drag reduction component, 4-rammer, 5-track, 101-cutting edge, 301-connecting bent pipe, 302-first grouting straight pipe, 303-second grouting straight pipe and 304-lock catch.

Detailed Description

Hereinafter, the tamping equipment for reducing the resistance of the wall of the tamping pipe and the tamping construction process thereof according to the present invention will be described in detail with reference to the accompanying drawings and exemplary embodiments. It should be noted that "first," "second," and the like are merely for convenience of description and for ease of distinction, and are not to be construed as indicating or implying relative importance. "front," "back," "left," "right," "inner," "outer," and the like are merely for convenience in describing and establishing relative orientations or positional relationships, and do not indicate or imply that the referenced components must have that particular orientation or position.

FIG. 1 shows a schematic structural view of a tamping apparatus for reducing the resistance of the wall of a tamping tube, according to an exemplary embodiment of the present invention; fig. 2 shows a schematic cross-sectional view of the steel casing of fig. 1 with a cutting ring installed.

One aspect of the present invention provides a tamping apparatus for reducing the resistance of a tamping tube wall.

In an exemplary embodiment of the invention, a tamping apparatus for reducing the resistance of a wall of a tamping tube includes a cutting ring, a steel casing, a slip casting drag reduction member, a tamping hammer body, and a track. Specifically, the tamping equipment for reducing the resistance of the pipe wall of the tamping pipe mainly comprises a cutting ring 1, a steel sleeve 2, a grouting resistance-reducing component 3, a tamping hammer body 4 and a track 5.

In this embodiment, as shown in FIG. 1, the track 5 is fixedly disposed on the ground for tamping of the steel casing 2 in a predetermined direction in the ground being cut on the track 5. Specifically, the rail 5 is mainly used for tamping the steel casing 2 in a predetermined direction and angle by the ram 4 hitting the steel casing 2, and thus the rail must be fixed to the ground. In order to prevent the settlement of the underlying stratum of the track in the tamping process and further seriously influence the track deviation design of the tamping pipe, the concrete reinforcement treatment is carried out on the earthquake of the track installation before the tamping pipe. For example, the track for pipe ramming construction may be an i-rail, a steel plate is laid under the track, and the track is fixed on the ground by a stable ground spear. Specifically, concrete with the thickness of about 30-50 cm and the plane size of about 18m multiplied by 2m is poured into a mold to lay a foundation by taking the longitudinal axis of the steel rail as a center line according to the length of the steel rail (generally 16-20 m), wherein the concrete is not less than C25, and the concrete is rectangular. After the concrete is initially set, leveling and angle confirmation are carried out on the foundation by using a level gauge and an angle ruler, and subsequent track installation and laying can be carried out after the requirement is met.

In this embodiment, the cutting ring 1 is fixedly disposed at the front end of the steel casing 2, a cutting edge (also called a bevel) 101 for cutting a soil body is disposed at one end of the cutting ring 1 not connected to the steel casing 2 (i.e., the front end of the cutting ring 1), and the diameter of the cutting ring 1 is greater than that of the steel casing 2 so as to form an annular space between the wall of the steel casing 2 and the cut formation. Specifically, the cutting ring 1 is mounted at the front end (namely the left end in fig. 1) of the steel sleeve 2 body to play a role in shearing and splitting stratum and pre-forming a hole, a certain annular space is formed between the stratum surrounding rock and the steel sleeve 2 body, the load (namely the ground stress) in the stratum surrounding rock can be unloaded due to the existence of the annular space, the resistance is prevented from being increased continuously after the contact surface between the pipe wall of the steel sleeve 2 and the surrounding rock is increased gradually, and a good guiding function is played for tamping the steel sleeve 2. That is to say, when in tamping, the rammer applies ramming force to the steel sleeve, the steel sleeve transmits the ramming force to the cutting ring so as to cut the stratum rock mass to form a hole channel for the steel sleeve 2 to enter, and an annular space is formed between the steel sleeve 2 and the inner wall of the stratum hole channel. The existence of annular space has not only reduced the resistance that the steel casing outer wall received, can also further reduce the resistance of the stratum that the steel casing outer wall received in the process of ramming into through pouring into emollient etc. into annular space.

In the embodiment, the material strength of the cutting ring 1 is not lower than that of the steel sleeve 2, an inner groove is obliquely formed on one side of the cutting ring 1, and the groove angle can be 30-40 degrees. Specifically, the cutting ring 1 is made of a material not lower than that of the steel pipe 2, for example, a steel material such as X70 or X80 is preferably used. An inward cutting edge 101 is arranged at the front end (i.e. the left end in fig. 2) of the cutting ring 1, and the angle of the cutting edge 101 is 30-40 °. Here, the angle of the cutting edge 101 refers to the included angle between the cutting edge 101 and the axis of the cutting ring 1, and the distance between the cutting edge 101 and the axis gradually decreases from left to right. Here, the cutting edge 101 is provided with like this and is favorable to cutting ring 1 to chop, the breakage to the stratum country rock in the pipe ramming process, also is favorable to the soil body by the breakage to get into the lumen of steel casing pipe 2 simultaneously, avoids the stratum to be unable discharge of piece after the breakage, overstocks in the stratum, causes huge reaction force (resistance) to steel casing pipe 2 body. Further, as shown in fig. 2, the front end of the steel casing 2 may be provided with an inward cutting edge, and the angle of the cutting edge of the steel casing 2 may be the same as that of the cutter ring 1. The wall thickness of the cutting ring 1 can be 1-3 times of that of the steel sleeve 2, the length of the cutting ring 1 can be 20-50 cm, the length of the part, which is not overlapped with the steel sleeve 2, of the cutting ring 1 can be 1-5 cm, and the cutting ring 1 and the steel sleeve 2 can be connected in a full-length welding mode. Specifically, the wall thickness of the cutting ring 1 is preferably set to 1 to 2 times the wall thickness of the steel casing 2, the length of the cutting ring 1 is preferably controlled within a range of 20 to 50cm, and the length of the portion of the cutting ring 1 not overlapping the steel casing 2 is preferably controlled to 1 to 5 cm. Here, the thickness of the cutting ring 1 is not necessarily too thin, and when the thickness of the cutting ring 1 is too thin, on the one hand, the strength of the cutting ring 1 is affected, and on the other hand, an annular space formed between a tunnel formed after cutting the earth rock mass and the outer wall of the steel casing 2 is not large enough. The cutting ring 1 and the steel sleeve 2 are connected in a full-length welding mode, the cutting ring 1 and the steel sleeve 2 are overlapped together in the connecting mode, and the radial deformation resistance of the steel sleeve 2 is improved. The pipe body of the steel sleeve 2 is pushed forward to form a stable pore passage section in the stratum, so that the pipe body at the rear part of the cutting ring 1 is not contacted with surrounding rocks as much as possible, and the friction force applied by the surrounding rocks to the wall of the steel sleeve 2 is greatly reduced. After the cutting ring 1 is manufactured and installed, the steel sleeve 2 needs to be hoisted to the track 5. The first casing with the cutting ring 1 is hung on the steel rail by using a crane, and the outer diameter of the part provided with the cutting ring 1 is larger than that of the pipe body, so that the part of the cutting ring 1 exceeds the front end of the steel rail, and the suspended section cannot exceed 1 m. At the same time, it is checked whether the rail is in seamless contact with the steel casing 2. If a contact gap occurs, the concrete foundation needs to be re-leveled and reformed. And (5) abutting an angle gauge right above the sleeve, and repeatedly measuring whether the angle of the sleeve is consistent with the hole entering angle required by the design.

In this embodiment, ram 4 is connected to the other end of steel casing 2 and is capable of applying a ramming force to steel casing 2. Specifically, as shown in FIG. 1, a ram 4 is attached to the rear end (i.e., the right end in FIG. 1) of the steel casing 2, and ramming is performed in the formation by the ram 4 applying a ramming force to the steel casing 2 to move the steel casing 2 on a track 5. The ramming apparatus may further comprise an air compressor connected to the ram 4 via a high pressure pipe to drive the ram 4 to generate a ramming force. Specifically, the air compressor provides a power source for the rammer 4, and the rammer 4 changes the output air pressure and frequency by adjusting an air compressor air pressure throttle valve so as to achieve the purpose of adjusting the ramming force. In the pipe tamping process, the tamping force output by the air compressor does not exceed the theoretical maximum value calculated according to the yield strength and the safety factor of the steel sleeve 2. Meanwhile, during construction, the opening of the throttle valve of the air compressor is adjusted according to the tamping speed, and the stability of the tamping speed is ensured.

In this embodiment, a slip casting drag reduction member 3 is disposed in the annulus above the outer wall of the steel casing 2 and is capable of pumping mud into the annulus to reduce frictional resistance between the outer wall of the steel casing 2 and the formation being cut. Specifically, the grouting drag reduction component 3 is arranged on the outer wall of the steel sleeve 2 and is positioned in an annulus formed between the outer wall of the steel sleeve 2 and the inner wall of a stratum pore passage, slurry is poured into the annulus through the grouting drag reduction component 3 during pipe tamping, mud cakes are formed on the inner wall of the stratum pore passage by the slurry, the friction force between the outer wall of the steel sleeve 2 and the inner wall of the stratum pore passage can be reduced, and the resistance received by the steel sleeve 2 is further reduced. For example, the grouting drag reduction part 3 may comprise a first straight grouting pipe, a second straight grouting pipe 303, a connecting elbow pipe 301 and a three-way connecting valve. The first grouting straight pipe 302, the second grouting straight pipe 303 and the connecting bent pipe 301 are respectively provided with an opening for pouring slurry into the annular space, the first grouting straight pipe 302 and the second grouting straight pipe 303 are respectively arranged on the outer wall of the steel sleeve 2 along the axial direction of the steel sleeve 2, the connecting bent pipe 301 is arranged on the outer wall of the steel sleeve 2 along the circumferential direction of the steel sleeve 2, two ends of the connecting bent pipe 301 are respectively connected with the first grouting straight pipe 302 and the second grouting straight pipe 303, and the three-way connecting valve is respectively connected with one ends, which are not connected with the connecting bent pipe 301, of the first grouting straight pipe 302 and the second grouting straight pipe 303.

In this embodiment, the first grouting straight pipe 302 and the second grouting straight pipe 303 may be axially disposed at ten and two points on the outer wall of the steel casing 2, and the first grouting straight pipe 302 and the second grouting straight pipe 303 are welded with the latches 304 at intervals to fix the first grouting straight pipe 302 and the second grouting straight pipe 303. The openings in first straight grout tube 302, second straight grout tube 303 and connecting elbow 301 may have different orientations. The diameter of the bend should be smaller than the wall thickness of the cutting ring 1. Specifically, the first grouting straight pipe 302 and the second grouting straight pipe 303 are small-caliber seamless steel pipes and are arranged at ten-point positions and two-point positions of the steel sleeve 2 in parallel, because the natural world mostly forms a conventional landform by horizontal extrusion force, and the pure extrusion force applied in the directions of the ten-point positions and the two-point positions is smaller than that applied in the directions of the 3-point positions and the 9-point positions, so that the risk of extrusion deformation of the grouting straight pipes can be reduced. Here, the ten-point position and the two-point position are ten-point and two-point orientations on the circumference of a cross section perpendicular to the steel casing 2, wherein the twelve-point orientation is directly above. In addition, the grouting straight pipe is likely to be subjected to shearing damage of surrounding rocks in the ramming process, and therefore the grouting straight pipe is fixed in a mode that the lock catches 304 are welded on the grouting straight pipe at intervals. The connecting bent pipe 301 is tightly attached to the outer wall of the grouting straight pipe, arranged at the lower part of the grouting straight pipe and contacted with or close to the rear end of the cutting ring 1, and the diameter of the connecting bent pipe 301 needs to be smaller than the wall thickness of the cutting ring 1, so that the connecting bent pipe 301 is reduced or prevented from being contacted with the inner wall of a stratum pore passage, and slurry can be poured into the annular space. Here, the connecting bent pipe 301 is used for connecting two grouting straight pipes, and may be connected by welding, the connecting bent pipe 301 is curved to be closely attached to the pipe wall, the connecting bent pipe 301 is provided with a plurality of pores which are arranged in different phases and used for injecting slurry in different directions, and the connecting bent pipe 301 is located behind the cutting ring 1 and is a main part for grouting lubrication. And arranging the perforated structure of the grouting pipe according to the designed tamping distance. First, as shown in fig. 3 and 4, 5 to 7 pores (with a diameter of 3 to 5mm) are formed at equal distances along the arc of the connecting elbow 301. The opening faces to form a sector spray coverage area from bottom to top, and the area around the sleeve is comprehensively washed and lubricated. And a pore (the pore diameter is less than 3mm, so that serious pressure relief during passing of slurry is avoided) is formed in the left and right symmetry of the grouting straight pipe close to the connecting bent pipe 301, and the connecting bent pipe 301 and the grouting straight pipe are connected in a welding mode. The slip casting straight tube (be first slip casting straight tube and second slip casting straight tube, the same below) is the annular passageway between ground mud injection sleeve pipe and the country rock, totally two, and parallel mount is in the sleeve pipe outside, tamps the length of pipe according to the design and can carry out the trompil at the anterior segment, if the distance is shorter, also can not trompil. The grouting straight pipe is also an auxiliary pipeline for grouting lubrication.

In this embodiment, the ramming apparatus may further comprise a mud pump connected to the three-way connection valve via a high pressure hose to deliver mud to the slip casting drag reduction unit 3. Here, the slurry pump is a device for supplying slurry to an annulus from the ground, and the slurry pump simultaneously injects the slurry into two straight grouting pipes through a high-pressure hose and a three-way valve. The mud pump must have sufficient capacity to avoid the lack of pressure to form a mud cake in the annulus as the mud flows through the grout tube opening.

The manufacturing and installation of the tamping equipment for reducing the resistance of the pipe wall of the tamping pipe comprises the following steps:

s1, customizing the overall scheme

Firstly, a field implementation general scheme is formulated according to the soil condition of a pipe ramming field and the design length of the pipe ramming field, and the field implementation general scheme comprises foundation reinforcement, manufacturing and installation of cutting rings, installation of grouting straight pipes and connecting bent pipes, hole opening, weight balancing of soil bodies coated on the axial lines, and grouting and ramming in a full-section time-sharing mode. Here, the total flow of the process construction is: foundation reinforcement → ground prefabrication and installation of cutting rings, positioning → installation of grouting pipes, hole opening → weighting of soil mass on the axis → tamping of grouting in full section and time sharing.

S2, process implementation analysis

The maximum value of the ramming force which can be borne by the steel sleeve is firstly calculated according to the material of the steel sleeve pipe, and then the maximum distance which can be reached by the ramming pipe is calculated according to the theoretical maximum value of the ramming force and by combining with geotechnical investigation report data. And determining the angle of the cutting edge of the cutting ring according to the lithology of the stratum. The principle of full-time grouting is adhered to, and the grouting discharge amount and the tamping force are adjusted according to the change of the tamping speed of the tamping pipe. The whole section indicates that the whole construction process is completed from the beginning to the end of the pipe ramming process, and equipment cannot be dismantled in the middle of the process. The time-sharing expression divides the grouting process into three processes of starting, tamping and tamping (welding and soil sampling) before a single sleeve is started, and grouting is only carried out in the first two processes. And stopping grouting when tamping is finished. Wherein, the underground grouting before starting is for reducing the start friction, carries out the piece that the body was dropped at the soil body of the period of stewing that stews simultaneously. The grouting in the tamping process is to carry broken soil fragments, reduce sliding friction resistance and newly form a hole section protecting wall.

S3, foundation reinforcement treatment

And concrete is required to be poured for soft soil stratum with lower bearing capacity of the foundation, and foundation reinforcement treatment is carried out.

S4, manufacturing, installing and positioning cutting ring

And after prefabrication of the cutting ring is finished, the cutting ring and the first steel sleeve are installed on the ground, the cutting ring is hoisted to the track to be in place, and after the cutting ring is in place, the contact tightness between the pipeline and the steel rail is checked and confirmed.

The grouting pipe installation and the perforated grouting straight pipe are small-caliber steel pipes and are installed at the rear end of the cutting ring until the ground is connected with the three-way valve. And the iron ring buckles are adopted to fix the grouting pipes on the outer wall of the sleeve at about ten points and two points. And (5) punching in the pipe ramming process, and continuing in a welding mode until the pipe ramming construction is completed.

The connecting bent pipe is tightly attached to the rear end and the pipe wall of the cutting ring, and the two grouting straight pipes are connected in a welding mode.

The grouting part is mainly connected with the bent pipe and assisted with the grouting straight pipe, and if the tamping distance is short, the grouting straight pipe is not provided with an opening.

S5, counterweight of earth mass on axis

In order to prevent the pipe from being buried deeply shallowly at the initial stage of pipe tamping, the bearing capacity of the soil body coated on the axis is weaker, so that the axis is deviated upwards, and the counter weight is required to be carried out in a mode of steel plate laying and heavy equipment or bagged soil piling within about 5m of the entrance of the sleeve.

Another aspect of the invention provides a tamping construction process for reducing the resistance of a long-distance tamping pipe wall. The ramming construction process aims at cohesive soil formations with plasticity index Ip larger than 10 and does not contain silt and mucky soil. The tamping construction process is mainly suitable for the stratum with higher cohesive soil content (namely the plasticity index Ip is more than 10, and the soil layer does not contain silt and mucky soil), and the tamping construction process has obvious effect of reducing the resistance of the pipe wall of the tamping pipe when tamping in the stratum. After the cohesive soil stratum is formed, the cohesive soil stratum has certain capacity to keep the structure of the pore canal stable. Therefore, the mud easily flows in the annular air formed by the cutting rings, so that the soil body scraps are convenient to carry, and the friction resistance is reduced. On the contrary, if the cutting ring is used in a non-viscous soil stratum, the cutting ring is difficult to form a hole, and the overlying soil body directly collapses around the pipeline. In addition, the mud also does not effectively lubricate and carry sand. The tamping construction process can be realized by the tamping equipment for reducing the resistance of the pipe wall of the tamping pipe, and the tamping construction process comprises the following steps:

firstly, a tamping device for reducing the resistance of the wall of the tamping pipe is manufactured and installed. Specifically, the tamping device for reducing the resistance of the wall of the tamping tube in the above-described embodiment is manufactured and installed for use.

And then, grouting in advance for a period of time before starting tamping, continuously grouting in the tamping process, recording the tamping force and the change of the tamping speed, and adjusting the tamping force according to the change of the tamping speed to keep the tamping speed within the range of 0.005-0.02 m/s until tamping is finished. Specifically, from the theoretical mechanical point of view, the starting frictional resistance of the steel casing pipe at the start of tamping is larger than the sliding frictional resistance after starting. Therefore, about 1min before the ram is started, the slurry should be poured into the annulus in advance. When the rammer is started, the annular space is basically filled with the slurry, a mud cake is formed in the annular space, the friction coefficient is reduced, and meanwhile, the effect of protecting the wall and stabilizing the hole is achieved to a certain extent. And continuously pumping slurry into the annular space through a grouting resistance reduction part in the tamping process, simultaneously closely monitoring the change conditions of the tamping force and the tamping speed, and adjusting the tamping force according to the change of the tamping speed to control the tamping speed to be within the range of 0.005-0.02 m/s until the tamping is finished. Here, when the tamping speed is less than 0.005m/s, the time required to complete tamping is too long, the wear on the tamping equipment is great, and there is also a risk of fatigue occurring in the sleeve. When the tamping speed is more than 0.02m/s, the tamping time is too short, and the broken soil fragments lack sufficient time to be discharged. Meanwhile, the tamping force is too large and may exceed the maximum tamping force which can be borne by the casing. For example, the tamping time of a single sleeve (usually 12m in length) is preferably controlled within 15-40 min, and the tamping speed is preferably controlled within 0.005-0.01 m/s. In actual operation, the impact strength caused by the tamping force is required to be smaller than the yield strength of the casing pipe, and meanwhile, the safety factor is also required to be considered.

In summary, the beneficial effects of the invention can include at least one of the following:

(1) the cutting ring is arranged at the front end of the steel sleeve, and the grouting anti-drag component is arranged on the outer wall of the steel sleeve, so that the frictional resistance of the stratum to the outer wall of the steel sleeve in the pipe tamping process is greatly reduced, the maximum distance for tamping the sleeve is increased, and the construction period for tamping the pipe is greatly saved;

(2) before the rammer is started, slurry is poured into the annular space in advance to form a mud cake on the annular space, so that the friction coefficient is reduced, and meanwhile, the wall protection and hole stabilization effects are achieved to a certain extent;

(3) the transition dependence on the performance of the rammer and the material of the pipe is improved, the aim of increasing the maximum ramming distance of the rammer pipe is fulfilled on the premise that the output energy of the rammer is limited, and meanwhile, the equipment consumption and the pipe purchasing cost are reduced.

Although the present invention has been described above in connection with the exemplary embodiments and the accompanying drawings, it will be apparent to those of ordinary skill in the art that various modifications may be made to the above-described embodiments without departing from the spirit and scope of the claims.

Claims

1. A tamping device for reducing the resistance of the pipe wall of a tamping pipe is characterized by comprising a cutting ring, a steel sleeve, a grouting resistance-reducing component, a tamping hammer body and a track, wherein,

the track is fixedly arranged on the ground so that a steel sleeve can be tamped in the cut stratum along a preset direction on the track;

the cutting ring is fixedly arranged at the front end of the steel sleeve, a groove for cutting a soil body is arranged at one end of the cutting ring, which is not connected with the steel sleeve, and the diameter of the cutting ring is larger than that of the steel sleeve, so that an annulus is formed between the wall of the steel sleeve and a cut stratum;

the rammer is connected with the other end of the steel sleeve and can apply ramming force to the steel sleeve;

the grouting drag reduction component is arranged in the annular space on the outer wall of the steel sleeve and can pump the slurry into the annular space so as to reduce the frictional resistance between the outer wall of the steel sleeve and the ground to be cut.

2. The ramming apparatus for reducing the resistance of the pipe wall of the ramming pipe according to claim 1, further comprising an air compressor connected to the ram via a high pressure pipe to drive the ram to generate the ramming force.

3. The ramming apparatus for reducing the resistance of a rammed pipe wall according to claim 1, wherein said slip casting drag reduction components comprise a first straight slip casting pipe, a second straight slip casting pipe, a connecting elbow, and a three-way connecting valve,

the grouting device comprises a first grouting straight pipe, a second grouting straight pipe and a connecting bent pipe, wherein the first grouting straight pipe, the second grouting straight pipe and the connecting bent pipe are respectively provided with a hole for filling slurry into the annular space, the first grouting straight pipe and the second grouting straight pipe are respectively arranged on the outer wall of a steel sleeve along the axial direction of the steel sleeve, the connecting bent pipe is arranged on the outer wall of the steel sleeve along the circumferential direction of the steel sleeve, the two ends of the connecting bent pipe are respectively connected with the first grouting straight pipe and the second grouting straight pipe, and a three-way connecting valve is respectively connected with one ends of the first grouting straight pipe and the second grouting straight pipe, which are not connected with the connecting bent pipe.

4. The tamper apparatus for reducing the resistance of a rammed pipe wall according to claim 3, wherein said openings in said first straight grout pipe, said second straight grout pipe and said connecting elbow have different orientations.

5. The ramming equipment for reducing the resistance of the pipe wall of the ramming pipe according to claim 3, wherein the first grouting straight pipe and the second grouting straight pipe are axially arranged at ten-point position and two-point position on the outer wall of the steel sleeve, and the first grouting straight pipe and the second grouting straight pipe are welded with latches at intervals to fix the first grouting straight pipe and the second grouting straight pipe.

6. The tamper apparatus for reducing the resistance of a rammed pipe wall according to claim 3, wherein said elbow has a diameter less than the wall thickness of said cutting ring.

7. The ramming apparatus for reducing the resistance of the walls of a rammed pipe according to claim 1, further comprising a mud pump connected to the tee connection valve via a high pressure hose to deliver mud to the slip reduction unit.

8. The tamping equipment for reducing the resistance of the pipe wall of the tamping pipe according to claim 1, wherein the wall thickness of the cutting ring is 1-2 times of that of the steel sleeve, the length of the cutting ring is 20-50 cm, the length of the part of the cutting ring which is not overlapped with the steel sleeve is 1-5 cm, and the cutting ring and the steel sleeve are connected in a full welding mode.

9. The tamping equipment for reducing the resistance of the pipe wall of the tamping pipe according to claim 1, wherein the material strength of the cutting ring is not lower than that of a steel sleeve, an inner groove is obliquely formed on one side, and the groove angle is 30-40 degrees.

10. A ramming construction process for reducing resistance of a pipe wall of a rammed pipe, the ramming construction process being applied to a cohesive soil formation with a plasticity index Ip > 10 and not containing silt and mucky soil, wherein the ramming construction process is implemented by the ramming equipment for reducing resistance of the pipe wall of the rammed pipe according to any one of claims 1 to 9, and the ramming construction process comprises the steps of: