阅读说明：本技术 一种隧道盾构掘进始发端头孤石区盾构机的掘进参数的控制工艺 (Tunneling parameter control process of tunnel shield tunneling starting end boulder area shield tunneling machine ) 是由 孙振川 王凯 杨振兴 郭璐 李凤远 周建军 陈桥 王发民 孙飞祥 潘东江 于 2019-11-22 设计创作，主要内容包括：本发明公开了一种隧道盾构掘进始发端头孤石区盾构机的掘进参数的控制工艺,针对隧道存在孤石的情况,通过泥仓建压、盾构推进速度控制、渣土开挖量的控制、同步注浆及二次注浆的控制,基本消除孤石的存在对盾构施工的影响,实现盾构施工的安全顺利进行。(The invention discloses a control process of tunneling parameters of a tunnel shield tunneling starting end boulder area shield tunneling machine, aiming at the situation that boulders exist in a tunnel, the influence of the boulders on shield construction is basically eliminated through mud chamber pressure building, shield propulsion speed control, muck excavation amount control, synchronous grouting and secondary grouting control, and the safe and smooth shield construction is realized.)

1. A control process for tunneling parameters of a tunnel shield tunneling starting end boulder area shield tunneling machine is characterized by comprising the following steps:

(1) pressure building of mud silo

The upper part of a tunnel body of a tunneling section of the shield boulder area is mainly provided with silt, a tunnel stratum is mainly provided with silt, mucky soil and partial silty clay, the stratum water permeability is not strong, a soil body formed by soil particles and pore water is taken as an object, the side pressure is directly calculated by the saturation gravity of the soil, and the pressure calculation of the section is determined by adopting a water-soil calculation mode:

Pa=γ*H*Ka+p

in the formula: gamma-formation saturation Severe (kN/m);

h- -tunnel top buried depth (m);

ka — initiative soil pressure coefficient Ka = tan2 (45 ° - Φ/2);

p- -ground load;

phi-the formation internal friction angle;

(2) shield propulsion speed control

When starting end boulder area excavation, the excavation parameters need to be adjusted in time, the shield advancing speed is strictly controlled according to the requirement of low penetration of a boulder excavation cutter, and the boulder excavation speed is set to be 6-10mm/min in combination with the requirements of penetration and cutter head rotating speed;

(3) control of muck excavation volume

According to various flow rates and densities measured by a flowmeter and a densimeter for feeding and discharging slurry, the actual excavation amount of each ring can be obtained:

B＝

in the formula: b-excavated volume

Q, S-slurry outlet flow and slurry inlet flow (derived from shield flowmeter)

Delta, β -slurry out specific gravity and slurry in specific gravity (obtained according to shield specific gravity meter)

t-tunneling time per ring

Designing excavation amount of each ring of shield tunneling:

B'=π*(D/2)²*(ρ₁N₁+ρ₂N₂+...ρ_nN_n)

in the formula: b' -design excavated volume

D-the diameter of the tunnel excavation,

ρ n-corresponding formation density

The Nn-n stratum accounts for the excavation face.

2. The control process of claim 1, further comprising the step (4) of controlling the simultaneous grouting and the secondary grouting, comprising the steps of:

① synchronous grouting

When the shield tail enters the tunnel for 20cm after being sealed by the two tunnel portal steel wire brushes, grouting the shield tail, and adopting cement mortar for synchronous grouting in the process of the boulder section tunneling; during grouting, the deformation condition of the portal sealing device must be closely concerned, grouting is stopped in time when slurry leakage occurs, and corresponding measures are taken in time to process according to specific conditions;

synchronous grouting is carried out in the shield tunneling process to fill an annular gap which is separated from the back of a shield tail pipe piece in time, full slurry filling is ensured, and composite sand is selected for grouting slurry; in order to effectively control the floating amount of the duct piece, stabilize the duct piece as early as possible and reduce the stress concentration and damage of the duct piece in the shield tunneling process; properly shortening the initial setting time of cement mortar, wherein the setting time is about 3-6 h, and the strength of the slurry is not less than 2.5Mpa;

② secondary grouting

The boulder section tunneling is to strengthen the secondary grouting construction, further control the upward floating of the segment, form a waterproof closed ring on the outer arc surface of the lining segment and effectively reduce the underground water buoyancy force on the segment;

according to the construction condition, in the tunneling process or after the segment installation is finished, if the water leakage of the segment at the tail of the shield, the segment floating up greatly, the settlement on the ground surface greatly or sudden dangerous situation occurs, starting a secondary grouting system; the grouting material adopts cement-water glass double-liquid slurry, the grouting is performed from the bottom grouting hole in bilateral symmetry and upwards in sequence, the cement adopts P.O 42.5.5 common cement, the water cement ratio adopts 1: 1; controlling the glass beauty degree to be 25-35 be; cement paste: 1 of water glass volume ratio: 1, the setting time of the double-liquid grout is about 40S, the deformation condition of the tunnel door sealing device must be closely concerned when grouting is carried out at the grouting pressure of 0.5-0.6 MPa, the grouting is stopped in time when grout leakage occurs, and an intermittent grouting method can be adopted.

3. The control process according to claim 1, wherein, in the step (2) of controlling the shield tunneling speed,

① when the shield is started, a shield driver needs to check whether a jack is in a top state, acceleration is not suitable to be overlarge before the advance and the finish of the advance, when the tunneling of each ring is started, the tunneling speed is gradually increased, the cutter is prevented from being impacted by the overlarge starting speed, in ② normal tunneling process of each ring, the tunneling speed value is kept constant as much as possible, fluctuation is reduced, so that the stability of the water pressure of a cut is ensured, the smoothness of a mud pipe is ensured, when the tunneling speed is adjusted, the tunneling speed is gradually adjusted, the impact disturbance of the sudden change of the speed to a stratum is avoided, the water pressure swing of the cut is overlarge, the speed of ③ advancing speed needs to meet the requirement of the grouting amount of each ring, a synchronous grouting system is always in a good working state, when the tunneling speed is selected ④, the low-speed and low-penetration tunneling speed are adopted, and abnormal damage of a cutter head and the cutter.

4. The control process as claimed in claim 1, wherein the control measure for the excavated volume of the dregs in the step (3) is as follows:

(1) reasonably building pressure, paying attention to the adjustment of the pressure in the cabin in the tunneling process, summarizing and analyzing parameters in the tunneling process, and adjusting a pressure building value by combining surface subsidence monitoring data, the change condition of the water level of the sea surface and the change condition of geology;

(2) the method comprises the steps of (1) optimizing and adjusting slurry parameters, carrying out corresponding slurry parameter adjustment according to the properties of different stratums in the tunneling process, paying attention to increase the specific gravity of slurry properly in the stratum with large permeability such as sand and the like, forming an effective mud film on an excavation surface and supporting the soil body of the excavation surface, and (3) controlling the cut pressure, keeping the pressure of an excavation bin stable, reducing pressure fluctuation as much as possible in the tunneling process, controlling the liquid level of an air cushion bin to be stable, strengthening slurry circulation on the stratum with large viscosity, and avoiding collapse of the excavation surface due to large pressure fluctuation caused by factors such as discharge stagnation.

Technical Field

The invention relates to a shield tunneling machine tunneling process, in particular to a control process of tunneling parameters of a shield tunneling machine in an end boulder area at the tunneling starting end of a tunnel shield.

Background

In recent years, with the continuous development of society, more and more rail transit constructions are carried out on a large scale, bedrocks are controlled and influenced by geological structure conditions, rock pulp components and surrounding rock material components, undenatured or slightly weathered hard spheroids, namely 'boulders', are easy to develop in the weathering process, more complicated engineering geological conditions are met in the construction process, and more difficult engineering geological problems are also met. The shield construction is high in automation and informatization degree and becomes a main mode of subway tunnel construction in China, the influence of the existence of the boulder on the shield construction is great, and ground settlement and equipment damage are easily caused, so that the construction period is influenced.

Disclosure of Invention

The invention provides a control process of tunneling parameters of a tunnel shield tunneling starting end boulder area shield machine, aiming at the characteristics of high strength, large thickness and wide distribution range of boulders of a tunnel section to be excavated and aiming at the safe and smooth shield construction.

A control process for tunneling parameters of a tunnel shield tunneling starting end boulder area shield machine. The method comprises the following steps:

(1) pressure building of mud silo

The upper part of a tunnel body of a tunneling section of the shield boulder area is mainly provided with silt, a tunnel stratum is mainly provided with silt, mucky soil and partial silty clay, the stratum water permeability is not strong, a soil body formed by soil particles and pore water is taken as an object, the side pressure is directly calculated by the saturation gravity of the soil, and the pressure calculation of the section is determined by adopting a water-soil calculation mode:

Pa=γ*H*Ka+p

in the formula: gamma-formation saturation Severe (kN/m);

h- -tunnel top buried depth (m);

ka — initiative soil pressure coefficient Ka = tan2 (45 ° - Φ/2);

p- -ground load;

phi-the formation internal friction angle;

(2) shield propulsion speed control

When starting end boulder area excavation, the excavation parameters need to be adjusted in time, the shield advancing speed is strictly controlled according to the requirement of low penetration of a boulder excavation cutter, and the boulder excavation speed is set to be 6-10mm/min in combination with the requirements of penetration and cutter head rotating speed;

(3) control of muck excavation volume

The residue soil excavation amount is one of important parameters in the slurry balance shield construction management, and the actual excavation amount of each ring can be obtained according to various flow rates and densities measured by a flowmeter and a densimeter for feeding and discharging slurry:

B＝

in the formula: b-excavated volume

Q, S-slurry outlet flow and slurry inlet flow (derived from shield flowmeter)

Delta, β -slurry out specific gravity and slurry in specific gravity (obtained according to shield specific gravity meter)

t-tunneling time per ring

Designing excavation amount of each ring of shield tunneling:

B'=π*(D/2)²*(ρ₁N₁+ρ₂N₂+...ρ_nN_n)

in the formula: b' -design excavated volume

D-the diameter of the tunnel excavation,

ρ n-corresponding formation density

The Nn-n stratum accounts for the excavation face.

Further, the method also comprises the step (4) of controlling synchronous grouting and secondary grouting, and comprises the following steps:

① synchronous grouting

When the shield tail enters the tunnel for 20cm after being sealed by the two tunnel portal steel wire brushes, grouting the shield tail, and adopting cement mortar for synchronous grouting in the process of the boulder section tunneling; during grouting, the deformation condition of the portal sealing device must be closely concerned, grouting is stopped in time when slurry leakage occurs, and corresponding measures are taken in time to process according to specific conditions;

synchronous grouting is carried out in the shield tunneling process to fill an annular gap which is separated from the back of a shield tail pipe piece in time, full slurry filling is ensured, and composite sand is selected for grouting slurry; in order to effectively control the floating amount of the duct piece, stabilize the duct piece as early as possible and reduce the stress concentration and damage of the duct piece in the shield tunneling process; the initial setting time of cement mortar is properly shortened, the setting time is about 3-6 h, and the strength of the slurry is not less than 2.5 Mpa.

② secondary grouting

The boulder section tunneling is to strengthen the secondary grouting construction, further control the upward floating of the segment, form a waterproof closed ring on the outer arc surface of the lining segment and effectively reduce the underground water buoyancy force on the segment;

according to the construction condition, in the tunneling process or after the segment installation is finished, if the water leakage of the segment at the tail of the shield, the segment floating up greatly, the settlement on the ground surface greatly or sudden dangerous situation occurs, starting a secondary grouting system; the grouting material adopts cement-water glass double-liquid slurry, the grouting is performed from the bottom grouting hole in bilateral symmetry and upwards in sequence, the cement adopts P.O 42.5.5 common cement, the water cement ratio adopts 1: 1; controlling the glass beauty degree to be 25-35 be; cement paste: 1 of water glass volume ratio: 1, the setting time of the double-liquid grout is about 40S, the deformation condition of the tunnel door sealing device must be closely concerned when grouting is carried out at the grouting pressure of 0.5-0.6 MPa, the grouting is stopped in time when grout leakage occurs, and an intermittent grouting method can be adopted.

Further, when the shield tunneling speed in the step (2) is controlled,

① when the shield is started, the driver needs to check whether the jack is tight, the acceleration should not be too high before starting and ending the advance.

② in each normal tunneling process, the tunneling speed should be kept constant as much as possible to reduce fluctuation to ensure stable cut water pressure and smooth mud pipe and mud pipe.

③ the propelling speed must meet the requirement of the tunneling grouting amount of each ring, and the synchronous grouting system is always in a good working state.

④ when the tunneling speed is selected, low-speed and low-penetration tunneling is adopted, and abnormal damage to a cutter head and a cutter of the shield tunneling machine caused by the fact that the arc stone is tunneled when the tunneling speed is too high is avoided.

Further, the control measures of the excavation amount of the muck in the step (3) are as follows:

(1) reasonably building pressure, paying attention to the adjustment of the pressure in the cabin in the tunneling process, summarizing and analyzing parameters in the tunneling process, and adjusting a pressure building value by combining surface subsidence monitoring data, the change condition of the water level of the sea surface and the change condition of geology;

(2) and (5) optimizing and adjusting slurry parameters. And adjusting corresponding slurry parameters according to the properties of different stratums in the tunneling process. In a stratum with high permeability such as sand, attention is paid to increase the specific gravity of mud properly, an effective mud film is formed on an excavation face, and a soil body of the excavation face is supported.

(3) The pressure of the cut is controlled, the pressure of the excavation bin is kept stable, pressure fluctuation is reduced as much as possible in the tunneling process, the liquid level of the air cushion bin is controlled to be stable, mud circulation is enhanced for the stratum with large viscosity, and the problem that the excavation face collapses due to large pressure fluctuation caused by factors such as discharge stagnation, bin blocking and the like is avoided.

The control process of the tunneling parameters of the tunnel shield tunneling starting end boulder area shield tunneling machine provided by the invention is used for basically eliminating the influence of boulder existence on shield construction and realizing safe and smooth shield construction by mud chamber pressure building, shield propulsion speed control, muck excavation amount control, synchronous grouting and secondary grouting under the condition that boulder exists in a tunnel.

Detailed Description

The invention relates to a control process of tunneling parameters of a tunnel shield tunneling starting end boulder area shield machine. The method comprises the following steps:

(1) pressure building of mud silo

The upper part of a tunnel body of a tunneling section of the shield boulder area is mainly provided with silt, a tunnel stratum is mainly provided with silt, mucky soil and partial silty clay, the stratum water permeability is not strong, a soil body formed by soil particles and pore water is taken as an object, the side pressure is directly calculated by the saturation gravity of the soil, and the pressure calculation of the section is determined by adopting a water-soil calculation mode:

Pa=γ*H*Ka+p

in the formula: gamma-formation saturation Severe (kN/m);

h- -tunnel top buried depth (m);

ka — initiative soil pressure coefficient Ka = tan2 (45 ° - Φ/2);

p- -ground load;

phi-the formation internal friction angle;

(2) shield propulsion speed control

When starting end boulder area excavation, the excavation parameters need to be adjusted timely, the shield advancing speed is strictly controlled according to the requirement of low penetration of a boulder excavation cutter, and the boulder excavation speed is set to be 8mm/min in combination with the requirements of penetration and cutter head rotating speed;

(3) control of muck excavation volume

The residue soil excavation amount is one of important parameters in the slurry balance shield construction management, and the actual excavation amount of each ring can be obtained according to various flow rates and densities measured by a flowmeter and a densimeter for feeding and discharging slurry:

B＝

in the formula: b-excavated volume

Q, S-slurry outlet flow and slurry inlet flow (derived from shield flowmeter)

Delta, β -slurry out specific gravity and slurry in specific gravity (obtained according to shield specific gravity meter)

t-tunneling time per ring

Designing excavation amount of each ring of shield tunneling:

B'=π*(D/2)²*(ρ₁N₁+ρ₂N₂+...ρ_nN_n)

in the formula: b' -design excavated volume

D-the diameter of the tunnel excavation,

ρ n-corresponding formation density

The Nn-n stratum accounts for the excavation face.

(4) The control of synchronous grouting and secondary grouting comprises the following steps:

① synchronous grouting

When the shield tail enters the tunnel for 20cm after being sealed by the two tunnel portal steel wire brushes, grouting the shield tail, and adopting cement mortar for synchronous grouting in the process of the boulder section tunneling; during grouting, the deformation condition of the portal sealing device must be closely concerned, grouting is stopped in time when slurry leakage occurs, and corresponding measures are taken in time to process according to specific conditions;

synchronous grouting is carried out in the shield tunneling process to fill an annular gap which is separated from the back of a shield tail pipe piece in time, full slurry filling is ensured, and composite sand is selected for grouting slurry; in order to effectively control the floating amount of the duct piece, stabilize the duct piece as early as possible and reduce the stress concentration and damage of the duct piece in the shield tunneling process; the initial setting time of cement mortar is properly shortened, the setting time is about 3-6 h, and the strength of the slurry is not less than 2.5 Mpa.

② secondary grouting

The boulder section tunneling is to strengthen the secondary grouting construction, further control the upward floating of the segment, form a waterproof closed ring on the outer arc surface of the lining segment and effectively reduce the underground water buoyancy force on the segment;

according to the construction condition, in the tunneling process or after the segment installation is finished, if the water leakage of the segment at the tail of the shield, the segment floating up greatly, the settlement on the ground surface greatly or sudden dangerous situation occurs, starting a secondary grouting system; the grouting material adopts cement-water glass double-liquid slurry, the grouting is performed from the bottom grouting hole in bilateral symmetry and upwards in sequence, the cement adopts P.O 42.5.5 common cement, the water cement ratio adopts 1: 1; controlling the glass beauty degree to be 25-35 be; cement paste: 1 of water glass volume ratio: 1, the setting time of the double-liquid grout is about 40S, the deformation condition of the tunnel door sealing device must be closely concerned when grouting is carried out at the grouting pressure of 0.5-0.6 MPa, the grouting is stopped in time when grout leakage occurs, and an intermittent grouting method can be adopted.

Further, when the shield tunneling speed in the step (2) is controlled,

① when the shield is started, the driver needs to check whether the jack is tight, the acceleration should not be too high before starting and ending the advance.

② in each normal tunneling process, the tunneling speed should be kept constant as much as possible to reduce fluctuation to ensure stable cut water pressure and smooth mud pipe and mud pipe.

③ the propelling speed must meet the requirement of the tunneling grouting amount of each ring, and the synchronous grouting system is always in a good working state.

④ when the tunneling speed is selected, low-speed and low-penetration tunneling is adopted, and abnormal damage to a cutter head and a cutter of the shield tunneling machine caused by the fact that the arc stone is tunneled when the tunneling speed is too high is avoided.

Further, the control measures of the excavation amount of the muck in the step (3) are as follows:

(1) reasonably building pressure, paying attention to the adjustment of the pressure in the cabin in the tunneling process, summarizing and analyzing parameters in the tunneling process, and adjusting a pressure building value by combining surface subsidence monitoring data, the change condition of the water level of the sea surface and the change condition of geology;

(2) and (5) optimizing and adjusting slurry parameters. And adjusting corresponding slurry parameters according to the properties of different stratums in the tunneling process. In a stratum with high permeability such as sand, attention is paid to increase the specific gravity of mud properly, an effective mud film is formed on an excavation face, and a soil body of the excavation face is supported.

(3) The pressure of the cut is controlled, the pressure of the excavation bin is kept stable, pressure fluctuation is reduced as much as possible in the tunneling process, the liquid level of the air cushion bin is controlled to be stable, mud circulation is enhanced for the stratum with large viscosity, and the problem that the excavation face collapses due to large pressure fluctuation caused by factors such as discharge stagnation, bin blocking and the like is avoided.

The control process of the tunneling parameters of the tunnel shield tunneling starting end boulder area shield tunneling machine provided by the invention is used for basically eliminating the influence of boulder existence on shield construction and realizing safe and smooth shield construction by mud chamber pressure building, shield propulsion speed control, muck excavation amount control, synchronous grouting and secondary grouting under the condition that boulder exists in a tunnel.