阅读说明：本技术 适用于长距离岩石顶管工程的减阻、阻隔石屑注浆方法 (Anti-drag and stone chip blocking grouting method suitable for long-distance rock pipe jacking engineering ) 是由 李永峰 吏细歌 胡祎 杨圣虎 刘凡 于 2020-04-17 设计创作，主要内容包括：本发明提供了一种适用于长距离岩石顶管工程的减阻、阻隔石屑注浆方法,包括下列步骤：S1、制作机尾管,并将机尾管设置于顶管机后端,机尾管上设置高压浓泥注浆孔；S2、拌浆：分别制作触变泥浆和高压浓泥；S3、安装注浆管；S4、注浆：顶管机顶进过程中,在前期顶力不大时只注入高压浓泥,当主顶油缸顶力达到10MPa时注入触变泥浆。本工法采用的高压浓泥具有“低失水性、高稳定性、高保压性”的特性,在管节周围合理位置预埋注浆管,使所注高压浓泥能够在管节外围形成一圈均匀稳定的浓稠泥浆套,配合触变泥浆能够较好地隔离管节外壁与土体间的缝隙,大大降低顶进阻力,提高施工效率。(The invention provides a drag reduction and stone chip blocking grouting method suitable for long-distance rock pipe jacking engineering, which comprises the following steps of: s1, manufacturing a machine tail pipe, arranging the machine tail pipe at the rear end of the push bench, and arranging a high-pressure thick mud grouting hole on the machine tail pipe; s2, slurry mixing: respectively preparing thixotropic slurry and high-pressure thick mud; s3, installing a grouting pipe; s4, grouting: in the jacking process of the pipe jacking machine, only high-pressure thick mud is injected when the jacking force is not large in the early stage, and thixotropic mud is injected when the jacking force of the main jacking oil cylinder reaches 10 MPa. The high-pressure thick mud adopted by the construction method has the characteristics of low water loss, high stability and high pressure maintaining performance, the grouting pipes are embedded at reasonable positions around the pipe joints, so that the injected high-pressure thick mud can form a circle of uniform and stable thick mud sleeve at the periphery of the pipe joints, and the gaps between the outer walls of the pipe joints and the soil body can be well isolated by matching with thixotropic mud, thereby greatly reducing jacking resistance and improving construction efficiency.)

1. The method for grouting the anti-drag and stone chip blocking for the long-distance rock pipe jacking project is characterized by comprising the following steps of:

s1, manufacturing a machine tail pipe, arranging the machine tail pipe at the rear end of the push bench, and arranging a high-pressure thick mud grouting hole on the machine tail pipe;

s2, slurry mixing: respectively preparing thixotropic slurry and high-pressure thick mud;

s3, installing a grouting pipe;

s4, grouting: in the jacking process of the pipe jacking machine, only high-pressure thick mud is injected when the jacking force is not large in the early stage, and thixotropic mud is injected when the jacking force of the main jacking oil cylinder reaches 10 MPa.

2. The method for drag reduction and stone chip blocking grouting suitable for long-distance rock pipe jacking engineering as claimed in claim 1, wherein: the high-pressure dense mud is prepared from bentonite, sodium carboxymethylcellulose, soda ash and water in parts by weight, wherein the bentonite accounts for 35%.

3. The method for drag reduction and stone chip blocking grouting suitable for long-distance rock pipe jacking engineering as claimed in claim 1, wherein: the grouting pipe consists of a main pipe and a branch pipe, the branch pipe is connected with the reserved grouting hole of the pipe joint and is provided with a valve, and a valve is arranged between the main pipe and the branch pipe.

4. The method for drag reduction and stone chip blocking grouting suitable for long-distance rock pipe jacking engineering as claimed in claim 1, wherein: during grouting, high-pressure thick mud is injected from a tail pipe and an originating tunnel portal of the push bench, and thixotropic mud is injected from the outer side of a middle pipe joint of the push bench.

5. The method for drag reduction and stone chip blocking grouting suitable for long-distance rock pipe jacking engineering as claimed in claim 1, wherein: and the high-pressure thick mud fills gaps formed when the jacking pipe is jacked in, and forms a stable mud sleeve around the pipe joint.

6. The method for drag reduction and stone chip blocking grouting suitable for long-distance rock pipe jacking engineering as claimed in claim 1, wherein: in step S4, a check valve is installed in the grouting hole to prevent soil outside the grout pipe from flowing backward to block the grouting hole, and the grouting equipment is checked by water injection before grouting.

7. The method for drag reduction and stone chip blocking grouting suitable for long-distance rock pipe jacking engineering as claimed in claim 1, wherein: and during grouting, the grouting pressure is strictly controlled, and is set between the active soil pressure and the passive soil pressure.

8. The method for drag reduction and stone chip blocking grouting suitable for long-distance rock pipe jacking engineering as claimed in claim 1, wherein: and grouting holes need to be timely supplemented when the jacking pipe is jacked.

Technical Field

The invention belongs to the technical field of pipe-jacking construction, and discloses a slip casting method for reducing drag and blocking stone chips, which is suitable for long-distance rock pipe-jacking engineering.

Background

With the continuous promotion of the urbanization construction process in China, the trenchless construction technology is more and more widely applied to construction projects such as pipe jacking, open caisson and drilling of urban comprehensive pipe networks, and due to the influence of the frictional resistance of soil bodies, the construction speed is restricted to a certain extent, and even the construction cannot be carried out. How to reduce the frictional resistance of the soil body and improve the non-excavation engineering construction work efficiency becomes an important technical problem in the technical field.

In order to solve the problem that the work efficiency of non-excavation engineering is influenced by the frictional resistance of soil bodies, a pressure grouting technology is generated by vast engineering technicians through annual technical research and development and innovative practice, a plurality of thixotropic slurry material ratios are generated, and the anti-drag method of the thixotropic slurry is generated accordingly.

In trenchless engineering construction such as pipe jacking, open caisson, drilling and the like, the drag reduction method of thixotropic slurry mainly has the following mechanism: the device has the functions of supporting and stabilizing the soil body and lubricating and drag reducing. As a newly developed auxiliary technology for non-excavation engineering construction, the excellent supporting and resistance reducing effects of the auxiliary technology are more and more accepted and popularized by the construction units, and the auxiliary technology has wide development prospect.

The pipe-jacking construction method is a common underground trenchless pipe-laying technology, and the friction force between a pipe and a soil body is large, so that the rear supporting force required to be provided during working is large, and even the supporting force cannot be provided, so that the construction is difficult. However, the method has the disadvantages that when thixotropic slurry is used for reducing the drag in pipe jacking construction, the intermittent construction downtime is long, so that the jacking force of the slurry after standing is greatly increased, enough jacking force and the back supporting force thereof are still needed to generate certain displacement to promote thixotropic drag reduction of the slurry, if the displacement cannot be generated, the thixotropic property can not be realized, the friction force can not be reduced, and the construction can not be continued.

In the long-distance pipe-jacking construction, drag reduction is one of the most important technical problems, and is a key technology for successfully completing pipe-jacking engineering. Thixotropic slurry is commonly used for reducing drag in domestic pipe jacking construction at present, and due to the limitation of performance of thixotropic slurry, the thixotropic slurry is easy to separate and lose water under the condition of continuous disturbance of jacking of the pipe jacking, so that the drag reduction is ineffective. The influence of the above conditions on the construction of the jacking pipe can be relieved to a certain extent by continuously supplementing thixotropic slurry in the jacking process. However, the position of the thixotropic slurry where the drag reduction fails is judged, and the targeted supplementary grouting is extremely difficult, so that the targeted supplementary grouting is not performed, great waste is caused, and the construction efficiency is greatly reduced; if the grouting is not timely, the jacking force is increased, and the risk of jacking failure is increased.

Disclosure of Invention

The invention aims to overcome the defects of the prior art and provides a slip casting method for reducing drag and blocking stone chips, which is suitable for long-distance rock pipe jacking engineering.

The invention is realized by the following steps:

the invention provides a drag reduction and stone chip blocking grouting method suitable for long-distance rock pipe jacking engineering, which comprises the following steps:

s1, manufacturing a machine tail pipe, arranging the machine tail pipe at the rear end of the push bench, and arranging a high-pressure thick mud grouting hole on the machine tail pipe;

s2, slurry mixing: respectively preparing thixotropic slurry and high-pressure thick mud;

s3, installing a grouting pipe;

s4, grouting: in the jacking process of the pipe jacking machine, only high-pressure thick mud is injected when the jacking force is not large in the early stage, and thixotropic mud is injected when the jacking force of the main jacking oil cylinder reaches 10 MPa.

Further, the high-pressure dense mud is prepared from bentonite, sodium carboxymethylcellulose, soda ash and water in parts by weight, wherein the bentonite accounts for 35%. Thixotropic slurry with water: the bentonite is prepared by mixing the bentonite in a ratio of 1: 0.1 and standing for not less than 8 hours, the high-pressure thick mud has higher consistency than thixotropic mud, and has better support performance, low permeability and high stability, the loss of the slurry in the jacking process is less, a slurry sleeve of about 30mm can be formed between the outer side of the pipe joint of the jacking pipe and a soil body, the pipe joint and the soil body are effectively isolated, and the effect of reducing the resistance is achieved.

Furthermore, the grouting pipe consists of a main pipe and a branch pipe, the branch pipe is connected with the reserved grouting hole of the pipe joint and is provided with a valve, and a valve is arranged between the main pipe and the branch pipe.

Furthermore, during grouting, high-pressure thick mud is injected from a tail pipe and an originating tunnel portal of the push bench, and thixotropic mud is injected from the outer side of a middle pipe joint of the push bench.

Further, the high-pressure thick mud fills gaps formed when the jacking pipe is jacked in, and a stable mud sleeve is formed around the pipe joint.

Further, in step S4, a check valve is provided in the grouting hole to prevent soil outside the grout pipe from flowing backward to block the grouting hole, and the grouting equipment is checked by water injection before grouting.

Furthermore, the grouting pressure is strictly controlled during grouting, and is set between the active soil pressure and the passive soil pressure.

Furthermore, when the jacking pipe is jacked, the grouting holes need to be timely supplemented with grout.

The invention has the following beneficial effects:

1. the grouting method prepares high-pressure thick mud with more excellent resistance reduction performance as resistance reduction mud by reasonably selecting materials and proportioning, and has low water loss, high stability and high pressure maintaining performance; the grouting pipes are embedded in reasonable positions around the pipe joints, so that the injected anti-drag slurry can form a circle of uniform and stable thick slurry sleeve on the periphery of the pipe joints, gaps between the outer walls of the pipe joints and a soil body can be well isolated, jacking resistance is greatly reduced, and construction efficiency is improved.

2. Compared with thixotropic slurry, the high-pressure thick mud has higher consistency and better flow plasticity. In the jacking process, the high-pressure thick mud can fill a gap between a soil body and a pipeline in time, so that the pipe wall and the surrounding soil body are effectively separated, and the pipe jacking machine and a pipe joint are prevented from being locked due to retraction of the soil body; when the rock stratum is tunneled, the tail pipe is beaten with mud, so that the pipe jacking machine and the pipe joints can be prevented from being clamped and dead due to rock debris deposition, the probability of occurrence of a 'jacking' accident is reduced, and the project can be smoothly completed.

3. The resistance reduction mode that adopts high-pressure dense mud and traditional thixotropic mud to combine together is showing very much to long distance push pipe reduction jacking resistance effect, and the relay ring sets up quantity in jacking length 763m and is reduced to 2 by 3, does not start the relay ring at the end after lining up, and to a great extent has reduced construction cost for the construction progress.

Detailed Description

The technical solutions in the embodiments of the present invention will be clearly and completely described below with reference to the embodiments of the present invention, and it is obvious that the described embodiments are only a part of the embodiments of the present invention, and not all of the embodiments. All other embodiments, which can be derived by a person skilled in the art from the embodiments given herein without making any creative effort, shall fall within the protection scope of the present invention.

The invention provides a drag reduction and stone chip blocking grouting method suitable for long-distance rock pipe jacking engineering, which comprises the following steps of:

s1, manufacturing a machine tail pipe, arranging the machine tail pipe at the rear end of the push bench, and arranging a high-pressure thick mud grouting hole on the machine tail pipe;

s2, slurry mixing: respectively preparing thixotropic slurry and high-pressure thick mud;

s3, installing a grouting pipe;

s4, grouting: in the jacking process of the pipe jacking machine, only high-pressure thick mud is injected when the jacking force is not large in the early stage, and thixotropic mud is injected when the jacking force of the main jacking oil cylinder reaches 10 MPa.

Example 1

The specific process flow in the embodiment is as follows: grouting construction preparation, slurry mixing, pipe joint grouting pipe installation, synchronous grouting, secondary slurry supplement and jacking completion, wherein a DN1650mm pipe jacking machine is adopted.

(1) Preparation for grouting construction

The tail pipe of the pipe jacking machine is manufactured, and the DN1650mm pipe jacking machine has small inner space and does not have the condition of mud beating in the machine head, so that a tail pipe of the machine with the length of 2m is arranged behind the pipe jacking machine and is specially used for mud beating operation, and grouting holes are reserved in a pipe joint and an originating hole.

(2) Slurry mixing device

The full-automatic high-speed stirring (grouting) trolley is adopted, and automatic metering, automatic feeding, optional loading, automatic speed and pressure regulation and computer liquid crystal screen display are carried out. After the thixotropic slurry is stirred, the thixotropic slurry can be used for grouting only by standing for not less than 8 hours, and the high-pressure thick slurry can be injected along with stirring.

(3) Installation slip casting pipe

The grouting pipe consists of a main pipe and a branch pipe, wherein the main pipe adoptsSteel pipe and branch pipeThe high-pressure rubber pipe of latus rectum, branch line and tube coupling reserve the slip casting hole and link to each other to install the ball valve, install the valve between house steward and the branch pipe.

(4) Synchronous grouting

High-pressure thick mud is injected into the tail pipe and the starting tunnel portal, and thixotropic mud is injected outside the middle pipe joint, so that the thixotropic mud is ensured not to flow into the front from the nose and not to flow out from the rear tunnel portal;

the jacking force is not large at the early stage, only high-pressure thick mud is injected, the jacking force of the main jacking oil cylinder reaches 10MPa, thixotropic slurry is injected at the same time, the principle of pressing first and then jacking, pressing along with jacking and timely slurry supplement is required during slurry pressing, the soil body stirred in the middle is uniformly filled with the high-pressure thick mud just like a coated film, the thixotropic slurry is prevented from permeating into the soil body, the performance of the thixotropic slurry is enhanced, and the pipe joint is effectively guaranteed to slide in a complete slurry sleeve.

The method comprises the following specific steps:

ground slurry mixing → start of slurry pressing pump → opening of valve of main pipe → opening of valve of pipe joint → slurry feeding (top start) → closing of valve of pipe joint (top stop) → closing of valve of main pipe valve → disassembly of quick joint in well → pipe joint of pipe laying → 2 cun main pipe connecting → circulation starting

A one-way valve is also arranged in the grouting hole to prevent backflow and blockage;

during grouting, the grouting pressure is strictly controlled, and slurry is prevented from flowing to the front end of the tool pipe and entering the pipe. The pressure of the thixotropic slurry is greater than the pressure of underground water, the slurry can permeate into a soil layer in a sol state, the pores of the soil layer can be sealed in a gel state after the slurry is static, the pressure of the thixotropic slurry is greater than the pressure of active soil, the thixotropic slurry can support the soil layer, the pressure of the thixotropic slurry is greater than the pressure of passive soil, and the soil layer can be damaged, so that the pressure of the thixotropic slurry is set between the pressure of the active soil and the pressure of the passive soil.

(5) Secondary pulp supplement

In the jacking process, due to the reasons of stratum crossing difference, jacking disturbance of a jacking pipe, long jacking time and the like, the mud after the pressure injection is easy to run off, and the mud needs to be timely supplemented to a mud jacking hole during jacking; if the ball valve is opened at the mud pressing hole at the top of the pipe joint, and the loss or segregation phenomenon of mud is found, the mud is supplemented at the mud pressing hole at the bottom of the pipe joint.

The above description is only for the purpose of illustrating the preferred embodiments of the present invention and is not to be construed as limiting the invention, and any modifications, equivalents, improvements and the like that fall within the spirit and principle of the present invention are intended to be included therein.