阅读说明：本技术 小曲率半径盾构施工分段纠偏方法 (Small-curvature-radius shield construction subsection deviation rectifying method ) 是由 路三平 邹峰 吴斌 罗云峰 李耀良 于 2019-11-19 设计创作，主要内容包括：本发明涉及一种小曲率半径盾构施工分段纠偏方法,其步骤为：(1)结合工程地质情况,施工前进行盾构机就位调试；(2)根据设计轴线的线形将每环隧道的掘进分为12小段,每段掘进长度100mm；(3)小曲线段施工时,定期复核盾尾后管片的轴线偏离值,并将测量值与历次测量值进行对比；(4)盾构推进过程应加强同步注浆,注浆应采用对角交替压注的方式进行；(5)施工过程中加强对电水平自动监测和地面沉降监测；(6)将测量数据与计算的控制值进行对比,盾构发生偏离时及时采取调整盾构区域油压措施对千斤顶行程差、盾构姿态进行调整。本发明可有效保证盾构施工过程中基坑的稳定性,防止因出现较大的偏差造成大幅度纠偏。(The invention relates to a segmented deviation rectifying method for shield construction with small curvature radius, which comprises the following steps: (1) in combination with the engineering geological condition, the shield machine is debugged in place before construction; (2) the tunneling of each ring of tunnel is divided into 12 segments according to the line shape of the designed axis, and the tunneling length of each segment is 100 mm; (3) during construction of the small curve segment, periodically rechecking the axis deviation value of the segment behind the shield tail, and comparing the measured value with the measured value of each time; (4) synchronous grouting should be strengthened in the shield propelling process, and the grouting should be carried out in a diagonal alternate pressure grouting mode; (5) enhancing automatic monitoring of the electric level and ground settlement monitoring in the construction process; (6) and comparing the measured data with the calculated control value, and adjusting the stroke difference of the jack and the shield attitude by taking measures for adjusting the oil pressure of the shield region in time when the shield deviates. The invention can effectively ensure the stability of the foundation pit in the shield construction process and prevent the large deviation from causing large deviation.)

1. A segmented deviation rectifying method for shield construction with small curvature radius is characterized by comprising the following steps:

(1) in combination with the engineering geological condition, the shield machine is debugged in place before construction;

(2) the tunneling of each ring of tunnel is divided into 12 segments according to the line shape of the designed axis, and the tunneling length of each segment is 100 mm;

(3) during construction of the small curve segment, periodically rechecking the axis deviation value of the segment behind the shield tail, and comparing the measured value with the measured value of each time;

(4) synchronous grouting should be strengthened in the shield propelling process, and the grouting should be carried out in a diagonal alternate pressure grouting mode;

(5) enhancing automatic monitoring of the electric level and ground settlement monitoring in the construction process;

(6) and comparing the measured data with the calculated control value, and adjusting the stroke difference of the jack and the shield attitude by taking measures for adjusting the oil pressure of the shield region in time when the shield deviates.

2. The small curvature radius shield construction subsection deviation rectifying method according to claim 1, characterized in that: the deviation rectifying control of the shield deviates the axis to the inner side of the axis by 20mm in advance so as to prevent the axis from exceeding the standard due to the outward movement of the tunnel, and the deviation of the shield cut and the shield tail is controlled within +/-20 mm by taking the deviation as a reference, namely the deviation value of the shield cut is controlled within-40-0 mm, and the deviation value of the shield tail is controlled within +/-20 mm.

Technical Field

The invention relates to a segmented deviation rectifying method for shield construction, in particular to a segmented deviation rectifying method for shield construction with small curvature radius.

Background

Along with the increase of urban construction speed, the scale is also continuously enlarged, and the population is rapidly expanded at the same time. The problems of land shortage, traffic jam, serious environmental pollution, aggravated energy consumption and the like appear in many cities to different degrees, which brings great influence to urban life and restricts the further development of economy and society. Nowadays, in the construction of subway tunnels in all cities in the world, shield construction is generally adopted. The underground shield is limited by planning, building and structures in line selection, so that the line shape of the tunnel is more and more complex, the ground surface settlement and the layered soil body movement can be caused in the shield tunneling process, and the physical and mechanical parameters of the soil body can also be changed. When the surrounding environment is complex, soil disturbance easily causes public nuisance, and curve tunnels with small curvature radius are usually needed to bypass dense buildings in cities and barriers such as various pipelines. From the long-term development of urban underground tunnels, the construction tasks of the tunnels with small curvature radius are more and more. Therefore, a segmented deviation rectifying method for shield construction with small curvature radius is needed.

Disclosure of Invention

The invention provides a segmented deviation rectifying method for shield construction with small curvature radius, which aims to solve the problems in the background technology.

The technical scheme of the invention is as follows: a segmented deviation rectifying method for shield construction with small curvature radius comprises the following steps:

(1) in combination with the engineering geological condition, the shield machine is debugged in place before construction;

(2) the tunneling of each ring of tunnel is divided into 12 segments according to the line shape of the designed axis, and the tunneling length of each segment is 100 mm;

(3) during construction of the small curve segment, periodically rechecking the axis deviation value of the segment behind the shield tail, and comparing the measured value with the measured value of each time;

(4) synchronous grouting should be strengthened in the shield propelling process, and the grouting should be carried out in a diagonal alternate pressure grouting mode;

(5) enhancing automatic monitoring of the electric level and ground settlement monitoring in the construction process;

(6) and comparing the measured data with the calculated control value, and adjusting the stroke difference of the jack and the shield attitude by taking measures for adjusting the oil pressure of the shield region in time when the shield deviates.

The deviation rectifying control of the shield deviates the axis to the inner side of the axis by 20mm in advance so as to prevent the axis from exceeding the standard due to the outward movement of the tunnel, and the deviation of the shield cut and the shield tail is controlled within +/-20 mm by taking the deviation as a reference, namely the deviation value of the shield cut is controlled within-40-0 mm, and the deviation value of the shield tail is controlled within +/-20 mm.

The invention has the beneficial effects that:

(1) the invention adopts a sectional construction method for construction, effectively ensures the stability of the foundation pit in the shield construction process, and can prevent large deviation correction caused by larger deviation.

(2) When the method is used for constructing a small curve segment, the axis deviation value of the segment after the shield tail is periodically rechecked, the measured value is compared with the measured value of the previous time, if the axis deviation value of the segment after the segment is separated from the shield tail is found to be changed, the reason is analyzed in time, if the segment is separated from the shield tail and then deviates to the outer side, a double-liquid slurry group is pressed and injected on the outer side wall of the curve by using a grouting hole on the segment to prevent the outer deviation of the tunnel from continuing to develop, and meanwhile, secondary slurry supplement is properly carried out on the inner side wall thickness of the curve according to the deviation value change quantity to prevent the inner side soil body from loosening.

(3) The invention adopts a diagonal alternate pressure injection mode in the shield advancing process, so that the pressure injected slurry is uniformly and continuously filled in the building gap behind the tunnel wall, and the synchronous grouting is controlled by adopting the double indexes of grouting quantity and grouting pressure.

(4) According to the invention, in the construction process of the shield, an included angle is always formed between the shield and the axis of the tunnel, so that a thrust force towards the outer side of a curve is formed by a shield jack to the tunnel behind the shield tail, therefore, the deviation of the shield cut and the shield tail is controlled within +/-20 mm by taking the deviation of the axis towards the inner side of the axis in advance as a reference to prevent the axis from exceeding the standard caused by the outward movement of the tunnel as a reference, namely, the deviation value of the shield cut is controlled within-40-0 mm, and the deviation value of the shield tail is controlled within +/-20 mm.

Detailed Description

The invention is further illustrated by the following examples.

The invention provides a segmented deviation rectifying method for shield construction with small curvature radius, which comprises the following steps:

(1) in combination with the engineering geological condition, the shield machine is debugged in place before construction;

(2) the tunneling of each ring of tunnel is divided into 12 segments according to the line shape of the designed axis, and the tunneling length of each segment is 100 mm;

(3) during construction of the small curve segment, periodically rechecking the axis deviation value of the segment behind the shield tail, and comparing the measured value with the measured value of each time;

(4) synchronous grouting should be strengthened in the shield propelling process, and the grouting should be carried out in a diagonal alternate pressure grouting mode;

(5) enhancing automatic monitoring of the electric level and ground settlement monitoring in the construction process;

(6) and comparing the measured data with the calculated control value, and adjusting the stroke difference of the jack and the shield attitude by taking measures of adjusting the oil pressure of the shield region and the like in time when deviation occurs.

Specifically, a tunnel in a certain engineering interval adopts prefabricated reinforced concrete segments, the inner diameter and the outer diameter of each segment are phi 5.5m and phi 6.2m respectively, the thickness of each segment is 350mm, the width of each segment is 1200mm, and the segments are assembled by adopting through seams. The lining has the design strength of C55, the anti-permeability labels of P10 and P12, and consists of a capping block XF, an adjacent block L1, an adjacent block L2, a standard block B1, a standard block B2 and a bottom block D. The minimum curve radius R of the tunnel plane between the A station and the B station is 350m, the maximum longitudinal slope of the tunnel is 27 per thousand, the center elevation of the tunnel is-16.601 m-25.758 m-16.895 m, and the top burial depth is 16.501 m-25.418 m-16.305 m.

The subway protection section requires a shield method for construction, and is assisted with synchronous grouting, automatic monitoring of the electric level and ground settlement monitoring.

The concrete subway line construction measures are as follows:

in combination with the engineering geological condition, the shield machine is debugged in place before construction, the initial construction divides the tunneling of each ring of tunnel into 12 segments, and the tunneling length of each segment is 100 mm; when entering the easement curve section, the posture of the shield tunneling machine deviates 15-20 mm towards the inner side (side close to the circle center) of the curve to form reverse pre-deviation, so that the deviation of the segment towards the outer side (back circle center side) of the curve is counteracted.

In the process of small-radius circular curve tunneling, the disturbance to the soil body can obviously reduce the strength and the self-stability capability of the peripheral soil body, the soil body has creep characteristic and uneven horizontal pressure, and the segment can integrally move outwards under the conditions that the segment bears the horizontal component force of a jack for a long time and the like. Synchronous slip casting and secondary slip casting are in time followed up, and the space between section of jurisdiction and the soil body is filled closely knit, reaches the effect that stabilizes the section of jurisdiction and reduces the earth's surface and subsides. When the shield machine turns, the synchronous grouting amount of each ring is increased by 15 percent compared with the normal synchronous grouting amount. The secondary grouting amount is determined to be carried out in the direction of the deviation of the duct piece according to the monitoring data. And (4) secondary grouting is carried out, the strength of the soil body on the outer side is increased to resist the deviation of the pipe piece, and after the slurry is solidified, the position of the pipe piece is basically determined. The tightening state of the bolts is adjusted, so that the overall rigidity of the tunnel is effectively improved, and the overall deflection of the formed tunnel is resisted.

The above description is only for the preferred embodiment of the present invention, but the scope of the present invention is not limited thereto, and any person skilled in the art should be considered to be within the technical scope of the present invention, and the technical solutions and the inventive concepts thereof according to the present invention should be equivalent or changed within the scope of the present invention.