阅读说明：本技术 一种高速铁路无砟轨道沉降囊式注浆抬升修复方法 (Sedimentation bag type grouting lifting repair method for ballastless track of high-speed railway ) 是由 苏谦 黄志超 黄俊杰 王迅 董敏琪 张宗宇 程李娜 裴彦飞 李茂� 王鑫越 于 2021-09-22 设计创作，主要内容包括：本发明公开了一种高速铁路无砟轨道沉降囊式注浆抬升修复方法,包括以下步骤：步骤1：计算抬升量H；步骤2：计算抬升力T,根据抬升力和聚氨酯膨胀力的关系,计算膨胀性聚氨酯配置密度ρ；步骤3：布设注浆抬升孔、注浆填充孔和观察孔；步骤4：安装注浆囊管、注浆填充管和观察管；步骤5：按照预先设计布置监测控制点,对线路高程、线路线形进行监控；步骤6：配置膨胀性聚氨酯,进行注浆抬升；步骤7：进行注浆填充；步骤8：拆除注浆囊管、注浆填充管和观察管,封闭钻孔部位,即完成注浆抬升修复；本发明提出了抬升力和聚氨酯配置密度的计算公式；创新了抬升工艺,工序简单,设备轻便化,可实现天窗内高速铁路无砟轨道沉降快速精确抬升修复。(The invention discloses a settlement bag type grouting lifting repair method for a ballastless track of a high-speed railway, which comprises the following steps of: step 1: calculating the lifting amount H; step 2: calculating a lifting force T, and calculating the configuration density rho of the expanded polyurethane according to the relationship between the lifting force and the polyurethane expansion force; and step 3: arranging a grouting lifting hole, a grouting filling hole and an observation hole; and 4, step 4: installing a grouting bag pipe, a grouting filling pipe and an observation pipe; and 5: arranging monitoring control points according to a preset design, and monitoring line elevation and line shape; step 6: preparing expanded polyurethane, and grouting and lifting; and 7: grouting and filling; and 8: removing the grouting bag pipe, the grouting filling pipe and the observation pipe, and sealing the drilling part to finish grouting lifting repair; the invention provides a calculation formula of the lifting force and the polyurethane configuration density; the lifting process is innovated, the process is simple, the equipment is portable, and the rapid and accurate lifting repair of the settlement of the ballastless track of the high-speed railway in the skylight can be realized.)

1. A high-speed railway ballastless track settlement bag type grouting lifting repair method is characterized by comprising the following steps:

step 1: each of the lengths L extending along both ends of the lifting repair remediation zone₀Comparing the actual elevation of the measured line with the original design elevation data of the line, wherein the difference value is the lifting amount H;

step 2: calculating a lifting force T, and calculating the configuration density rho of the expanded polyurethane according to the relationship between the lifting force and the polyurethane expansion force;

and step 3: according to the lifting amount obtained in the step 1 and the pre-design, grouting lifting holes (3) are distributed at the joint of the base plate (2) and the sealing layer (9); grouting filling holes (4) are distributed at the joints of the base plate (2) and the side surfaces of the track plate (1); arranging observation holes (5) at the positions corresponding to the grouting filling holes (4) at the side surface seams of the base plate (2) and the sealing layer (9);

and 4, step 4: a grouting bag pipe (8) is arranged at a position corresponding to the grouting lifting hole (3), a grouting filling pipe (10) is arranged at a position corresponding to the grouting filling hole (4), and an observation pipe (11) is arranged at a position corresponding to the observation hole (5);

and 5: arranging monitoring control points (6) according to a preset design, and monitoring line elevation and line shape;

step 6: preparing expanded polyurethane according to the density calculated in the step 2, and starting grouting and lifting by adopting a grouting bag pipe (8); stopping grouting after the height is raised to a preset height;

and 7: grouting filling is carried out through the grouting filling pipe (10), and the elevation change of the track slab is monitored in real time;

and 8: and after grouting filling is finished, the grouting bag pipe (8), the grouting filling pipe (10) and the observation pipe (11) are removed, and the drilling part is sealed, so that grouting lifting repair is finished.

2. The high-speed railway ballastless track settling bag type grouting lifting repair method according to claim 1, wherein the grouting bag pipe (8) comprises a bag body and a grouting rod body connected with the bag body through a one-way valve.

3. The high-speed railway ballastless track settlement bag type grouting lifting repair method according to claim 2, wherein the lifting force calculation method in the step 2 is as follows:

T＝G_buckle+G_Rail+F

In the formula: g_BuckleIs the dead weight of the fastener G_RailThe self-weight of the track structure is adopted, and F is the bonding force of the base plate (2) and the surface layer (7) of the foundation bed.

4. The high-speed railway ballastless track settlement bag type grouting lifting repair method of claim 3, wherein the calculation process of the configuration density p of the expanded polyurethane in the step 2 is as follows:

P_f＝aρ²+bρ+c

in the formula: p_fThe expansion force of polyurethane, a, b and c are coefficients;

wherein, P_fThe calculation method is as follows

T＝P_f×S

In the formula: s is the contact area of the capsule body and the base plate (2).

5. The high-speed railway ballastless track settling bag type grouting lifting repair method according to claim 1, wherein the step 3 grouting lifting hole (3) drilling method comprises the following steps:

drilling downwards along the joint of the base plate (2) and the sealing layer (9) in an inclined angle of 45 degrees, wherein the drilling depth is not more than the lifting amount;

the drilling method of the grouting filling hole (4) comprises the following steps:

drilling downwards along the joint of the track plate (1) and the sealing layer (9) in an inclined angle of 45 degrees, wherein the drilling depth does not exceed the lifting amount;

the drilling method of the observation hole (5) is as follows:

drilling downwards along the joint of the track plate (1) and the base plate (2) at an angle of 45 degrees until the drilling reaches the top surface of the surface layer (7) of the foundation bed.

6. The high-speed railway ballastless track settling bag type grouting lifting repair method according to claim 5, wherein the grouting lifting holes (3) and the grouting filling holes (4) are distributed in a staggered manner; the aperture of the grouting lifting hole (3) and the aperture of the grouting filling hole (4) are both 35 mm; the distance L between the adjacent grouting lifting holes (3)₁No more than 2m, and the distance L between adjacent grouting filling holes (4)₃Not more than 2.4 m; the aperture of the observation holes (11) is 8-15 mm, and the distance L between adjacent observation holes (11)₃Not more than 2.4 m; the distances between the grouting lifting hole (3) and the grouting filling hole (4) and between the grouting lifting hole (3) and the observation hole (11) are L₂None of them exceed 1.5 m.

7. The high-speed railway ballastless track settlement bag type grouting lifting repair method according to claim 1, characterized in that a high-precision multi-point video dynamic and static displacement detection system is adopted to dynamically monitor line elevation and line alignment; the monitoring control point (6) is arranged on a rail bearing platform at the fastener side outside the steel rail; in the lifting repair and remediation area, the interval between monitoring control points (6) does not exceed 2 sleeper intervals; monitoring control points (6) arranged on the track slab (1) and adjacent to two ends of the lifting repair and remediation area are spaced by 3 sleeper intervals; a high-precision target (12) is arranged on the monitoring control point (6).

8. The method for repairing the ballastless track of the high-speed railway by sedimentation bag type grouting lifting according to claim 1, wherein in the grouting lifting process in the step 6, the grouting sequence starts to lift from the area with the largest sedimentation amount to the two ends of the track synchronously from the two sides of the track.

9. The high-speed railway ballastless track settlement bag type grouting lifting repair method according to claim 1, wherein in the step 7, grouting is sequentially and synchronously grouting and filling along two sides; in the grouting filling process, the diffusion condition of the grout is monitored through the observation pipe (11) in real time, and when the grout overflows from the observation pipe (11), the grouting filling operation close to the grouting filling hole (4) is stopped;

and monitoring the elevation change of the track slab (1) in real time, stopping grouting and filling when the elevation change of the track exceeds 1mm, reducing grouting pressure, and restarting grouting and filling until grouting and filling are finished.

10. The high-speed railway ballastless track settlement bag type grouting lifting repair method according to claim 1, characterized by further comprising the following steps:

recovering the fastener system after grouting and lifting reach a preset target, and adjusting the track; retesting the track line shape through a total station to obtain a new height and a new coordinate of the monitoring control point (6); and comparing the data with the original data before lifting to obtain the lifting effect.

Technical Field

The invention relates to the technical field of high-speed railway operation and maintenance, in particular to a settlement bag type grouting lifting repair method for a ballastless track of a high-speed railway.

Background

By the end of 2020, the operating mileage of the high-speed railway reaches 3.8 kilometers in China, and the high-speed railway line network is basically formed. This shows that the high-speed railway in China will enter a long-term operation and maintenance stage from large-scale construction, and ensuring the safe and stable operation of the high-speed railway line is one of the major problems faced by the high-speed railway in China. The high-speed railway in China largely adopts ballastless track structures, and the structures have good integrity, smoothness and durability, but are greatly influenced by the settlement of off-line infrastructure. The current railway design specifications in China put forward strict requirements on the post-construction settlement of infrastructure under a ballastless track line, wherein the post-construction settlement of a common section of a roadbed is not more than 15mm, and the post-construction differential settlement limit value of a transition section at the tail of a bridge abutment is 5 mm. The high-speed railway has high running speed, high density and large transportation capacity, and the subgrade can not avoid settlement deformation under the action of long-term train load due to comprehensive reasons such as the difference of geology along the line, the regionality and variability of properties of rock-soil materials, the complexity of natural environmental operation change, the limitation of geotechnical design theory, investigation and construction technology and the like. Roadbed settlement diseases appear in partial operation high-speed railway sections in China, and exceed the design specification requirements of high-speed railways, so that the trains slow down and move slowly when passing through the settlement sections, and the operation safety, comfort and transportation efficiency of the high-speed railways are seriously influenced.

The current disposal methods for the ballastless track settlement problem mainly include three methods: (1) the first is to replace the fastener system. When the foundation settlement under the current line is small, the lifting of the steel rail can be realized by adjusting the thickness of the gasket in the fastener system, and the smoothness of the line is recovered, but the fastener system is inevitably worn under the action of long-term dynamic load, so that the settlement damage is generated again, and the thickness of the gasket is limited, so that the repairing method has poor effect. (2) The second method is mechanical lifting, which is to open a groove on a closed layer near the side of a base plate, arrange a jack, realize lifting of a track structure by the jacking force of the jack, and then fill the bottom of the plate with cement mortar. The method has great damage to the track structure, influences the safety of the track structure, is difficult to control the jacking process, and is easy to generate the phenomenon of over-lifting or little lifting. The cement mortar is a rigid material, and under the action of long-term dynamic load, graded broken stones in the surface layer of the foundation bed are rubbed and crushed with the cement mortar, so that the interlayer contact characteristic is deteriorated, and the power transmission is not facilitated. (3) The third method is to use high polymer grouting to lift, such as the grouting and lifting rapid repairing method for sinking the ballastless track (201310382596.1), the grouting and lifting method for sinking the ballastless track (201611244651.0) and the grouting and lifting method for the high-speed railway and the grouting material (201910062029.5) which are all provided by the patent, namely the grouting and lifting track structure by using the expansive high polymer material. The essence of the method is that high polymer slurry with expansibility is injected into graded broken stones on the surface layer of the foundation bed through an injection pump, and the track structure is lifted by means of the diffusion expansion force and the injection pressure of the high polymer slurry. However, the diffusion mechanism of the high polymer slurry in the graded broken stone is complicated, and the expansion force loss is caused along with the slurry diffusion, so that the matching relation between the grouting amount and the lifting amount is not clear. The grouting lifting operation is implemented according to experience, the actual lifting effect is greatly different from theoretical calculation, and the unit price of the material is high, so that the engineering cost is increased, and the grouting lifting operation is not suitable for large-area use. The patent 'a ballastless track grouting lifting and lifting deviation rectifying method (201710013063.4)' proposes that a method of combining a polymer bag and a jack is adopted to carry out lifting deviation rectifying on the ballastless track. Although the method can limit the flow of the grout, the sealing layer needs to be cut and the middle of the track plate needs to be drilled, the damage to the track structure is large, and under the condition of vertical drilling and grouting, the polymer bag generates large expansion force on two sides under the pressure of the grout, the vertical expansion force is uncontrollable, and the lifting effect is difficult to control. Such methods have not been practiced at present. The 'method for grouting high polymer in the ballastless track lifting of the high-speed railway (201310123669.5)' proposes that the track structure is lifted by arranging a geotextile bag under a base plate, then injecting expansive high polymer into the geotextile bag, and limiting the flow of slurry by means of the geotextile bag to exert the expansive force of the high polymer. The method can avoid slurry leakage and slurry leakage, and is favorable for exerting the expansion force. However, there are the following problems: the length of the grouting hole, namely the length of the geotextile bag is consistent with the transverse width of the base plate, so that the construction on the existing line is complicated; the direct contact area between the base plate and the surface layer of the foundation bed is reduced by the arrangement mode of full length, and power transmission is not utilized; under the action of long-term dynamic load, a large area of geotextile bags and the base plate are repeatedly rubbed and are easily damaged under the puncture action of graded broken stones.

Disclosure of Invention

The invention provides a bag type grouting lifting repair method for a ballastless track of a high-speed railway, which is convenient to construct, economical and controllable in expansion, aiming at the problems in the prior art.

The technical scheme adopted by the invention is as follows:

a settlement bag type grouting lifting repair method for a ballastless track of a high-speed railway comprises the following steps:

step 1: each of the lengths L extending along both ends of the lifting repair remediation zone₀Comparing the measured line elevation with the original designed line elevation data, wherein the difference is the lifting amount H;

step 2: calculating a lifting force T, and calculating the configuration density rho of the expanded polyurethane according to the relationship between the lifting force and the polyurethane expansion force;

and step 3: according to the lifting amount obtained in the step 1 and the pre-design, grouting lifting holes are distributed at the joint of the base plate and the sealing layer; arranging grouting filling holes at the joints of the side surfaces of the base plate and the track plate; arranging observation holes at the corresponding positions of the grouting filling holes at the side seams of the base plate and the closed layer;

and 4, step 4: installing grouting bag pipes at corresponding positions of the grouting lifting holes, installing grouting filling pipes at corresponding positions of the grouting filling holes, and installing observation pipes at corresponding positions of the observation holes;

and 5: arranging monitoring control points according to a preset design, and monitoring line elevation and line shape;

step 6: preparing expanded polyurethane according to the density calculated in the step 2, and starting grouting and lifting by adopting a grouting bag pipe; stopping grouting after the height is raised to a preset height;

and 7: grouting and filling are carried out through a grouting and filling pipe, and the elevation change of the track slab is monitored in real time;

and 8: and after grouting filling is finished, removing the grouting bag pipe, the grouting filling pipe and the observation pipe, and sealing the drilling part to finish grouting lifting repair.

Furthermore, the grouting bag tube comprises a bag body and a grouting rod body connected with the bag body through a one-way valve.

Further, the lifting force calculation method in step 2 is as follows:

T＝G_buckle+G_Rail+F

In the formula: g_BuckleIs the dead weight of the fastener G_RailThe self-weight of the track structure is adopted, and F is the bonding force between the base plate and the surface layer of the foundation bed.

Further, the calculation process of the configuration density ρ of the expanded polyurethane in the step 2 is as follows:

P_f＝aρ²+bρ+c

in the formula: p_fThe expansion force of polyurethane, a, b and c are coefficients;

wherein, P_fThe calculation method is as follows

T＝P_f×S

In the formula: s is the contact area of the capsule body and the base plate.

Further, the grouting lifting hole drilling method in the step 3 is as follows:

drilling downwards along the joint of the base plate and the closed layer by inclining 45 degrees, wherein the drilling depth is not more than the lifting amount;

the grouting filling hole drilling method comprises the following steps:

drilling downwards along the joint of the track plate and the sealing layer at an angle of 45 degrees, wherein the drilling depth does not exceed the lifting amount;

the method for drilling the observation hole comprises the following steps:

and drilling downwards along the joint of the track plate and the base plate at an angle of 45 degrees to the top surface of the surface layer of the foundation bed.

Furthermore, the grouting lifting holes and the grouting filling holes are distributed in a staggered mode; the aperture of each grouting lifting hole and the aperture of each grouting filling hole are both 35 mm; spacing L between adjacent grouting lifting holes₁Not more than 2m, and the interval L between adjacent grouting filling holes₃Not more than 2.4 m; the aperture of each observation hole is 8-15 mm, and the distance L between every two adjacent observation holes₃Not more than 2.4 m; the distances between the grouting lifting hole and the grouting filling hole as well as between the grouting lifting hole and the observation hole are all L₂None of them exceed 1.5 m.

Further, a high-precision multi-point video dynamic and static displacement detection system is adopted to dynamically monitor the line elevation and the line shape; the monitoring control points are arranged on the rail bearing platform at the fastener side outside the steel rail; in the lifting repair treatment area, the interval of monitoring control points does not exceed 2 sleeper intervals; monitoring control points arranged on the track slab at two ends of the lifting repair and remediation area and close to the track slab are spaced by 3 sleeper intervals; and setting a high-precision target on the monitoring control point.

Furthermore, in the grouting lifting process in the step 6, the grouting sequence starts to lift from the area with the largest settling amount to the two ends along the two sides of the line synchronously.

Furthermore, in the grouting filling process in the step 7, the grouting sequence is directionally and synchronously grouted and filled along two sides; in the grouting filling process, monitoring the diffusion condition of the grout through the observation pipe in real time, and stopping grouting filling operation close to a grouting filling hole when the grout overflows from the observation pipe;

and monitoring the elevation change of the track slab in real time, stopping grouting and filling when the elevation change of the track exceeds 1mm, reducing grouting pressure, and restarting grouting and filling until grouting and filling are finished.

Further, the method also comprises the following steps:

recovering the fastener system after grouting and lifting reach a preset target, and adjusting the track; retesting the track line shape through a total station to obtain a new elevation and a new coordinate of the monitoring control point; and comparing the data with the original data before lifting to obtain the lifting effect.

The invention has the beneficial effects that:

(1) the lifting force and the polyurethane density required by lifting are determined by combining theoretical calculation and an indoor test, and the polyurethane lifting device has theoretical support and is more reliable;

(2) the bag-type grouting is adopted, the bag body part of the grouting bag tube well limits the diffusion and flow of the slurry, the phenomena of slurry leakage, slurry leakage and expansion force dissipation of the slurry are avoided, the expansion performance of polyurethane is fully exerted, and the lifting efficiency and the lifting accuracy are improved;

(3) the grouting bag pipe is installed according to the designed point position and is grouted and lifted, so that the fixed-point accurate lifting of the track structure can be realized, and the lifting efficiency and the lifting accuracy are improved;

(4) the lifting hole positions and the observation hole positions are uniformly distributed on the closed layer, and grouting filling holes are only drilled in the base plate, so that the damage to the track structure is small;

(5) the depth of the grouting bag pipe inserted into the surface layer of the foundation bed is limited, the disturbance on the surface layer of the foundation bed is small, and the influence on the contact characteristic of the surface layer of the foundation bed and a base plate is small;

(6) the method has the advantages of innovating a lifting process, being simple in process, lightening equipment, saving human resources, reducing engineering cost and realizing rapid and accurate lifting and repairing of the settlement of the ballastless track of the high-speed railway in the skylight.

Drawings

FIG. 1 is a schematic view of a line shape measurement area according to the present invention.

FIG. 2 is a plan view of grouting lifting holes, grouting filling holes, observation holes and monitoring points according to the present invention.

FIG. 3 is a schematic plan view of the distance between the grouting lifting hole, the grouting filling hole and the observation hole according to the present invention.

FIG. 4 is a schematic cross-sectional view of the arrangement of grouting lifting holes in the invention.

FIG. 5 is a schematic cross-sectional view showing the arrangement of the grouting filling holes and the observation holes in the present invention.

In the figure: 1-track plate, 2-base plate, 3-grouting lifting hole, 4-observation hole, 5-grouting filling hole, 6-monitoring control point, 7-bed surface layer, 8-grouting bag tube, 9-sealing layer, 10-grouting filling tube, 11-observation tube, 12-high precision target and 13-steel rail.

Detailed Description

The invention is further described with reference to the following figures and specific embodiments.

A settlement bag type grouting lifting repair method for a ballastless track of a high-speed railway comprises the following steps:

step 1: each of the lengths L extending along both ends of the lifting repair remediation zone₀Comparing the actual elevation of the measured line with the original design elevation data of the line, wherein the difference value is the lifting amount H;

in the detailed description of the process L₀Taking 50m, measuring line elevation and coordinate data by using an electronic level and a total station, and finally determining the lifting amount to be 2 cm.

Step 2: calculating a lifting force T, and calculating the configuration density rho of the expanded polyurethane according to the relationship between the lifting force and the polyurethane expansion force; the grouting bag tube 8 comprises a bag body and a grouting rod body connected with the bag body through a one-way valve. The lifting force calculation method is as follows:

T＝G_buckle+G_Rail+F

In the formula: g_BuckleIs the dead weight of the fastener G_RailThe self-weight of the track structure is adopted, and F is the bonding force of the base plate 2 and the surface layer 7 of the foundation bed. The lift force in this example was calculated to be 197.2 kN.

The expanded polyurethane configuration density ρ is calculated as follows:

P_f＝aρ²+bρ+c

in the formula: p_fThe expansion force is polyurethane expansion force, a, b and c are coefficients and can be determined according to an indoor expansion force experiment;

wherein, P_fThe calculation method is as follows

T＝P_f×S

In the formula: s is the contact area of the capsule body and the base plate 2 and can be determined according to an indoor grouting single-point lifting model test.

The polyurethane expansion force P was calculated in this example_fAt 880.51kPa, the calculated expanded polyurethane had a density of 0.25g/cm³。

And step 3: according to the lifting amount obtained in the step 1 and the pre-design, grouting lifting holes 3 are distributed at the joint of the base plate 2 and the sealing layer 9; grouting filling holes 4 are distributed at the joints of the side surfaces of the base plate 2 and the track plate 1; and arranging observation holes 5 at the positions corresponding to the grouting filling holes 4 at the side seams of the base plate 2 and the closed layer 9.

3 apertures 35mm of grouting lifting holes and 3 intervals L between adjacent grouting lifting holes₁The maximum is not more than 2 m. This arrangement avoids major damage to the base plate 2 and, on the other hand, allows the grouting bag tube 8 to extend below the base plate 2. The grouting lifting hole 3 drilling process is as follows: and drilling downwards along the joint of the base plate 2 and the closed layer 9 in an inclined angle of 45 degrees, wherein the drilling depth does not exceed the lifting amount.

The aperture of each grouting filling hole is 4 mm, and the distance L between adjacent grouting filling holes is 4₃The maximum is not more than 2.4 m. The track structure design drawing is combined and a steel bar scanner is used for detecting the distribution of the steel bars, so that the steel bars are prevented from being damaged during drilling. Meanwhile, the grouting filling holes 4 and the grouting lifting holes 3 are distributed in a staggered mode and distributed in a quincunx shape. Drilling downwards along the joint of the track plate 1 and the base plate 2 at an inclined angle of 45 degrees, wherein the drilling depth does not exceed the lifting amount.

The aperture of the observation hole 11 is 8-15 mm, and the hole spacing L3 is not more than 2.4 m; drilling downwards along the joint of the track plate 1 and the base plate 2 at an angle of 45 degrees until the top surface of the surface layer 7 of the foundation bed is drilled. The distance between the grouting lifting hole 3 and the grouting filling hole 4, and the distance between the grouting lifting hole 3 and the observation hole 11 are not more than 1.5 m.

And 4, step 4: a grouting bag pipe 8 is arranged at a position corresponding to the grouting lifting hole 3, a grouting filling pipe 10 is arranged at a position corresponding to the grouting filling hole 4, and an observation pipe 11 is arranged at a position corresponding to the observation hole 5; the grouting bag tube 8 comprises a bag body and a grouting rod body. The grouting sack body 8 is made of high-strength geosynthetic material, and the sack body is connected with the grouting rod body through a one-way valve, wherein the length of the straight section of the grouting rod body is b₁Not less than the distance b between the side surface of the track slab 1 and the edge of the base plate 2₂The outer diameter is 30mm, the puncture strength is not less than 1.5MPa, and the tensile strength is not less than 2 MPa. And (4) penetrating the grouting bag pipe 8 into the middle position of the base plate 2 along the grouting lifting hole. The vertical height h of the grouting filling pipe 10 inserted into the surface layer 7 of the foundation bed does not exceed the lifting amount. In order to prevent the slurry from flowing out along the gap between the grouting filling pipe 10 and the hole under the grouting pressure, a quick-setting high polymer material is adopted for sealing. The observation tube 11 is made of polypropylene or polyvinyl chloride with the same aperture as the observation hole 5, and is inserted into the bed surface layer 7 along the observation hole 5.

And 5: monitoring the line elevation and the line shape according to a pre-designed arrangement monitoring control point 6; the dynamic monitoring in the lifting process is a necessary means for evaluating the lifting effect, is limited by the operation time of skylight points, and adopts a high-precision multi-point video dynamic and static displacement detection system to carry out comprehensive full-time dynamic monitoring on the line elevation and the line shape in order to improve the operation efficiency, wherein the precision of the detection system is not less than 0.1 mm. The monitoring control point 6 is arranged on a fastener side rail bearing platform on the side of the steel rail 13. In the lifting repair treatment area, the interval of the monitoring control points 6 is not more than 2 sleeper intervals; monitoring control points 6 which are arranged on the track slab 1 and close to two ends of the lifting repair and remediation area are spaced by 3 sleeper intervals; and a high-precision target 12 is arranged on the monitoring control point 6, and the CP III point is used as a reference point of the plane monitoring network.

Step 6: preparing expanded polyurethane according to the density calculated in the step 2, and starting grouting and lifting by adopting a grouting bag pipe 8; stopping grouting after the height is raised to a preset height; according to the operation requirement, special equipment for grouting of the expanded polyurethane is customized, the maximum output pressure is 20MPa, and the grouting speed is 2-10 kg/min. The equipment is provided with a slurry meter, and the grouting amount can be recorded in real time. The two-component polyurethane with expansibility is selected as a grouting lifting material, the selected polyurethane slurry has the characteristics of quick setting and early strength, the foaming expansion reaction time can be regulated and controlled as required, the expansion can be finished within 1min at the fastest speed, and the strength can reach 95% within 20 min. Preparing two-component polyurethane with required density, starting special equipment for injecting the expanded polyurethane, adjusting parameters such as injection pressure, slurry heating temperature and the like, then pulling a switch of an injection gun, injecting the materials into an empty barrel, and testing the free foaming performance such as initial reaction time, foaming curing time, expansion characteristic and the like of the foamed polyurethane slurry. The initial reaction time of the material is ensured to be between 5 and 15 seconds, the expansion curing time is not more than 40 seconds, the cell structure of a cured body generated by the material expansion reaction is uniform, and the color and the strength are consistent with the indoor test result. The grouting sequence starts to rise from the area with the largest sedimentation amount to the two ends along the two sides of the line in principle. And in the grouting lifting process, monitoring the elevation change of the track in the whole process uninterruptedly in real time, and stopping grouting after the track is lifted to a preset elevation.

And 7: grouting filling is carried out through the grouting filling pipe 10, and grouting is stopped when the track elevation change exceeds a preset value; the grouting equipment is a conventional grouting pump, and the interlayer gap is filled by adopting high-fluidity polymer modified cement. And connecting the grouting pump with the grouting filling pipe 10, and performing directional synchronous grouting filling along two sides. In the grouting filling process, the diffusion condition of the grout is monitored through the observation hole pipe 11 in real time, and when the grout overflows from the observation pipe 11, namely the interlayer pores in the area on the surface are filled, the grouting filling operation of the adjacent holes can be stopped. And in the grouting filling process, the elevation change of the track slab 1 is uninterruptedly monitored in real time, and when the elevation change of the track exceeds 1mm, grouting filling is immediately stopped, grouting pressure is reduced, and grouting filling is restarted.

And 8: and after grouting filling is completed, removing the grouting bag pipe 8, the grouting filling pipe 10 and the observation pipe 11, and sealing the drilling part to complete grouting lifting repair. After grouting filling is completed, standing for no more than 30min, cutting the grouting bag pipe 8 and the grouting filling pipe 10, and removing the observation pipe 11. And filling and sealing the drilling part by using a high-strength shrinkage-free quick-setting composite material. And (3) carrying out nondestructive detection on the sealing layer with a good surface, detecting whether a cavity exists below the sealing layer, if the cavity exists, which is caused by solidification, expansion and jacking of the polyurethane slurry, continuing drilling and grouting, wherein the injected material is polymer modified mortar, and sealing the grouting hole after the cavity is filled compactly.

Recovering the fastener system after grouting and lifting reach a preset target, and adjusting the track; retesting the track line shape through a total station (adopting a high-precision automatic total station), and acquiring a new elevation and a new coordinate of the monitoring control point 6; and comparing the data with the original data before lifting to obtain the lifting effect. If necessary, the construction can be carried out on the individual points.

The lifting force and the density of the polyurethane required by lifting are determined by adopting a theoretical calculation formula and combining an indoor test, and the technology is supported by theory and is more reliable. The bag body part of the grouting bag tube can well limit the diffusion and flow of the slurry, and the phenomena of slurry leakage, slurry leakage and expansion force dissipation of the slurry are avoided. The polyurethane expansion performance is fully exerted, and the lifting efficiency and the lifting accuracy are improved. The grouting bag pipe is installed according to the design point position and lifted by grouting, so that the fixed-point accurate lifting of the track structure can be realized, and the lifting efficiency and accuracy are improved. Grouting lifting hole sites and observation hole sites are uniformly distributed on the closed layer, and grouting filling holes are drilled only in the base plate, so that the damage to the track structure is small. The polyurethane used in the invention can be expanded and cured within 5-10 min, so that the lifting purpose is realized. The high-strength polymer modified cement mortar can meet the use requirement of the cementing and solidifying within 30min and meet the requirement of the operation time limit of skylight points. The elastic modulus of a combination formed by solidifying the polymer modified cement mortar serving as a filling material and the graded broken stone on the surface layer of the foundation bed is moderate. The uniform transition of the vertical rigidity of the track-roadbed is realized, and the long-term dynamic stability of the roadbed structure is facilitated. The method has the advantages of innovating a lifting process, being simple in process, lightening equipment, saving human resources, reducing engineering cost and realizing rapid and accurate lifting repair of ballastless track settlement in the skylight.