CN108049878B - A kind of powder land floor shield cuts the construction method that stake is crossed the river - Google Patents

Abstract

The present invention relates to a kind of powder land floor shields to cut the construction method that stake is crossed the river, comprising: material prepares；Shield cuts pile foundation concrete measure: cut pile driving construction control, monitoring control, under wear river Construction control, the working measure of ambiguous barriers, pipeline protection measure；Shield driving parameter setting；Under wear the working measure in river；Control technology after shield crossing pile foundation；Monitoring frequency control；Control is maked an inspection tour in hole.The beneficial effects of the present invention are: method and step is simple, design is reasonable and construction is simple is convenient, input cost is lower, and it is strong that Practical Project operates implementation；The method, which can be improved down, through the invention wears drivage efficiency, controls attitude of shield machine, to reduce a possibility that accident occurs for tunnel, lays advantageous basis for subsequent successfully pass through；Practical value is high and using effect is good, compared to bored tunnel construction method is worn under existing, shortens the construction period, larger to reduce construction cost.

Description

A construction method for silt soil layer shield cutting piles to cross the river

technical field

The invention belongs to the technical field of shield tunnel cutting and excising existing pile foundations, and in particular relates to a construction method for shield tunnel cutting piles to cross rivers in silty soil.

Background technique

In recent years, with the large-scale construction of urban subways and related municipal projects, shield tunnels have been used more and more in China. During the shield tunnel crossing stage, it is often encountered that the existing building pile foundation needs to be pulled out and other construction methods to remove the pile foundation, so that the shield tunnel can cross normally. Higher, often can not achieve the expected construction effect.

There are many risks in using ordinary pile cutting construction methods. For example, if the tunneling speed of the shield machine is too fast in the process of cutting piles, it is easy to cause the shield machine to get stuck. It is difficult to control the attitude during the excavation process. If the shield machine is caused to move forward in a serpentine shape, it will also increase the risk of the shield machine being stuck; the shield machine may also be seriously damaged, which will affect the subsequent construction. The excavated pile tip and the broken pile head may advance with the shield machine to cause over-excavation of the stratum, which affects the control of ground subsidence and the safety of subsequent houses and pipelines; in addition, the shield screw conveyor may be stuck by steel bars. The shield machine is not functioning properly. After the shield machine cuts the pile foundation, the steel bar in the pile foundation will enter the screw conveyor, and the steel bar may be stuck in the gap between the screw blade and the inner wall of the screw machine sleeve, causing the screw machine to be stuck and affecting the later excavation; The latter pile will act on the tunnel segment with a point load, and transfer the load directly to the tunnel lining. During the operation of the subway, the interaction between the tunnel and the bridge will bring hidden dangers to the safe use of both; when the shield machine crosses the river When the overburden is shallow and the soil stability is poor, it is easy to cause perforation of the river bottom and river water backflow.

SUMMARY OF THE INVENTION

The purpose of the present invention is to overcome the deficiencies in the prior art, and provide a construction method for silt soil layer shield cutting piles to cross the river, the method steps are simple, the design is reasonable, the construction is simple and the construction effect is good, and the existing pile foundation Cut out and successfully traverse the formation with short cycle times and low cost.

The purpose of this invention is to realize through the following technical solutions:

The construction method of the silty soil layer shield cutting piles to cross the river includes the following steps:

1) Material preparation: make preparations for the secondary grouting after the segment wall; overhaul the secondary grouting equipment in advance; Impact drill for grouting holes; preparation of cement, water glass, check valve and hand hole plug for grouting;

2) Specific measures for shield cutting pile foundation: pile cutting construction control: the shield controls the important parameters of earth pressure, cutter head torque, grouting pressure and excavation amount in the process of cutting pile foundation; monitoring control: arranging measuring points to measure Good initial value, before the shield passes through the pile foundation or after the shield passes through the pile foundation, do a good job of monitoring the tunnel axis, ground settlement deformation and building deformation, and control the whole construction process according to the monitoring data; If the shield height is less than double the diameter of the shield, the bridge should be reinforced before advancing, and the protection of the short-distance bridge piles and the prevention of river water perfusion should be strengthened at the same time; Pay attention to the change of the torque of the cutter head and the change of the thrust during the propulsion process; pipeline protection measures: check and implement the pipelines along the section before construction; during the entire construction process of cutting piles and crossing the river, make the bentonite injection system When the earth pressure changes suddenly or the excavation footage does not match the unearthed amount, inject bentonite into the soil bin, and the injection pressure is higher than the earth pressure during excavation;

3) Setting of shield propelling parameters: when the shield passes through the pile foundation, the propelling speed and earth pressure parameters are controlled; when the shield approaches the pile foundation, the propelling speed is slowed down, and lubricant is added to the cutter head; When the cutter head is close to the pile foundation, the advancing speed is slowed down; when the cutter head of the shield machine cuts the pile, the cutter grinds and cuts the concrete and steel bars at a slow pushing speed; under the condition of a certain pushing speed, the cutter head cuts the pile at a medium speed; The soil tank pressure is set. During the dynamic excavation process, the soil pressure is kept at a high level. First, close the dump gate and push the shield forward. When the soil tank pressure rises to a higher level than the set soil tank pressure, manually Unearthed, control the opening rate of the gate not to exceed 10%, close the gate after the soil tank pressure drops to the set soil tank pressure, continue to push, and so on; The amount of slurry refers to the excavation of the shield in the same soil layer in the early stage, and then adjusts according to the monitoring data of bridge settlement; when grouting, the pressing position, pressing amount and pressure value are recorded in detail, and the adjustment is made according to the monitoring information of formation deformation. ;The shield is constructed at a balanced and uniform speed, controlling the change of the attitude of the shield, and checking the leading amount of the segment in each ring; when advancing, the steady slope method and the gentle slope method are used to advance; the attitude control is performed during the process of cutting piles of the shield, and the cutter head and the pile are used when cutting piles. The body is in full contact with each other, and there is no deviation between the two; the bentonite is injected on the front of the shield cutter head to improve the workability of the excavation surface soil, and the amount and pressure of the bentonite are controlled when adding bentonite. The unearthed amount matches each other; equipped with a handheld infrared thermometer to judge the internal temperature of the soil bin; close the front and rear gates when the screw machine spout occurs; regularly check the shield tail grease pipeline and grease pump, and select good quality shield tail grease; through daily excavation Record and understand the working conditions of the shield tail grease injection system, predict the failure in advance, and repair it;

4) Construction measures for crossing the river: control the earth pressure balance of the shield; control the propelling speed of the shield; control the amount of shield deviation correction: check and adjust the posture of each segment during advancement, adopt the steady slope method and the gentle slope method to advance, Make the shield advance in a balanced and uniform speed, control the amount of correction to reduce the impact of shield construction on the ground; control the amount of synchronous grouting and the quality of the slurry;

5) Control technology after the shield passes through the pile foundation: After the shield tail of the shield falls out of the pile foundation area, the tunnel in this area is grouted for two to four times, and the specific grouting amount is adjusted according to the monitoring data of ground settlement.

As a priority: Before step 1), check the shield equipment, check the simultaneous grouting system, foam injection system, check the earth pressure balance system, check the shield tail grease injection system, check the hinge sealing system, check the drainage system in the tunnel, check communication system.

As a priority: in the step 3), when the cutter head of the shield machine cuts the pile, the cutter grinds and cuts the concrete and steel bars at a slow pushing speed of 1~3mm/min, and the thrust and torque of the shield machine are controlled to be 13000~18000kN and 2500~ 3500kN m.

As a priority: in the step 3), under the condition of a constant pushing speed, the cutter head cuts the pile at a medium speed of 1.2-1.5 rpm.

As a priority: in the step 4), the propelling speed of the shield is controlled at 2-3 cm/min.

As a priority: in the step 4), if necessary, fill soil conditioner into the soil bin.

The beneficial effects of the present invention are:

(1) The method steps are simple, the design is reasonable, the construction is simple and convenient, the input cost is low, and the practical engineering operation is strong;

(2) The method of the present invention can improve the efficiency of underpassing and control the attitude of the shield machine, thereby reducing the possibility of accidents in the tunnel, and laying a favorable foundation for subsequent successful crossing;

(3) The practical value is high and the use effect is good. Compared with the existing underpass tunnel construction method, the construction period is shortened and the construction cost is greatly reduced;

(4) It has a wide range of applications, and can be effectively applied to all underground tunnel construction and shield reinforcement, especially complex strata and other geological conditions with complex geological conditions, ensuring the smooth progress of the subsequent shield tunnel crossing work.

Description of drawings

FIG. 1 is a flow chart of the method of the present invention.

Figure 2 is a cross-sectional view of the positional relationship between the shield tunnel and the pile foundation

Figure 3 is a schematic diagram of the wear-resistant welding thickening of the cutter head.

Figure 4 is a schematic diagram of the layout of the L-shaped baffle at the inspection hole.

Figure 5 is a cross-sectional view of the layout of the L-shaped baffle at the inspection hole.

Description of reference numerals: 1—shield; 2—pile foundation; 3—wear-resistant welding thickened layer of cutter head; 4—L-shaped block; 5—excavation of screw machine; 6—inspection hole; 7—inspection hole cover Board sliding area.

Detailed ways

The present invention will be further described below in conjunction with the embodiments. The following examples are illustrative only to aid in the understanding of the present invention. It should be pointed out that for those skilled in the art, without departing from the principle of the present invention, several improvements and modifications can also be made to the present invention, and these improvements and modifications also fall within the protection scope of the claims of the present invention.

As shown in Figure 1, a construction method of a silty soil layer shield cutting piles to cross the river is the process flow. The cross-sectional view of the positional relationship between shield 1 tunnel and pile foundation 2 as shown in Figure 2. The shield machine cutter head has large alloy circles on both sides and a strip of alloy in the middle to ensure that the entire cutting surface is made of alloy. The two sides of the advanced concrete cutting knife are designed with large rounded corners, which can reduce the impact when the cutter head rotates; the blade on the top of the advanced concrete cutting knife is relatively narrow, and the force is small, which is easy to cut, and is more conducive to cutting when it comes into contact with the steel bar. As shown in Figure 3, a 3mm thick wear-resistant welding is added to the cutter head panel to form the cutter head wear-resistant welding thickened layer 3. If the cutter head cuts the pile foundation 2 during the process of the shield 1 passing through the pile foundation 2, the broken concrete blocks the excavation opening 5 of the screw machine, resulting in poor excavation of the screw machine, so that the propulsion cannot be continued. When the screw is stuck, make emergency preparations before opening the inspection hole 6 and cutting the probe hole. As shown in Figures 4 and 5, at this time, two-way parallel welding L-shaped block 4 around the inspection hole 6 or the position of the pre-opened exploration hole. The L-shaped block 4 can be cut from a 3-5cm thick steel plate. The stopper 4 is connected with the inspection hole 6 by bolts, and in an emergency, the cover plate is pushed into the direction of the sliding area 7 of the inspection hole cover plate, and the bolts are tightened. The specific size of the L-shaped block 4 is determined by considering the space when the cover plate is inserted and without affecting the installation bolts.

In fact, when the shield 1 passes through the pile foundation 2, if the pile foundation 2 is broken, the construction measures are as follows:

1) Shield 1 injects additives, such as foam and bentonite, for soil improvement. And through the forward and reverse rotation of the cutter head, the broken pile is cut into the soil bin or squeezed out.

2) If the broken pile affects the construction of shield 1, shield 1 will stop advancing. Use the grouting hole of the main body of the shield machine to carry out advanced grouting in front of the shield machine, so that the soil in front of the shield machine has a certain strength and ensure the uniformity of the soil strength on the excavation surface of the shield machine 1. Construct 1 excavation.

3) Carry out warehouse opening construction when necessary.

The specific process is as follows:

1) Shield machine equipment inspection:

1-1) Inspection of synchronous grouting system and foam injection system

Clean the grouting pipeline to ensure that all four pipelines can be used; comprehensively inspect and maintain the grouting pump to ensure that it is available; repair the grouting pressure sensor to ensure that each grouting pressure is displayed correctly; Clean up the road, especially the foaming agent pipe before entering the cutter head, to ensure that it is available.

1-2) Check the earth pressure balance system

The shield machine should replace the new pressure sensor (soil bin pressure sensor and screw conveyor pressure sensor) before starting, and pay close attention to the pressure change during the early excavation process, analyze whether the pressure sensor is damaged, and replace it in time if it is damaged.

1-3) Check the shield tail grease injection system

In order to ensure that the shield tail grouting does not leak or less, and prevent the shield tail from "squirting", the shield oil injection system must be overhauled to ensure that the grease pump works normally and the grease pipeline is unobstructed. Adjust the grease injection pressure to ensure that the grease is injected quantity.

1-4) Check the hinged sealing system

In order to prevent the hinged seal from leaking or even "gushing" due to the failure of the hinged seal, the hinged seal system must be overhauled. During the sand excavation process, the hinged seal system must be inspected and maintained at the required frequency in accordance with the mechanical management regulations to ensure it is in good condition.

1-5) Check the drainage system in the tunnel

In order to prevent the construction from being affected by the "squirting" of the shield tunnel 1, the drainage and sewage system in the tunnel must be thoroughly cleaned and inspected, and sufficient diaphragm pumps should be prepared for backup.

1-6) Check the communication system

The upper and lower communication lines and equipment must be overhauled to ensure smooth upper and lower communication during construction and in emergencies.

2) Preparation of other materials:

Make preparations for the secondary grouting after the segment wall, so that the secondary grouting measures can be started at any time. Overhaul the secondary (two-fluid) grouting equipment in advance to ensure availability. Prepare 6 to 8 grouting heads, prepare 10 to 15m long grouting pipes that can be well connected to the grouting head and the grouting machine, and prepare two impact drills for opening the grouting holes in the segments. The daily reserve of cement is not less than 20t, the daily reserve of water glass is not less than 2t, and there are several check valves and hand hole plugs for grouting.

3) Shield 1 cutting pile foundation 2 Specific measures:

3-1) Pile cutting construction control

When cutting piles, the advancing speed must be slowed down, and the parameters of the shield machine should be set reasonably. In the process of cutting pile foundation 2, shield 1 must strictly control various important parameters such as earth pressure, cutter head torque, grouting pressure, and excavation volume, so as to minimize the occurrence of overall displacement of pile foundation 2 itself during the advancing process.

3-2) Monitoring control

Arrange the measuring points to measure the initial value; before or after the shield 1 crosses the pile foundation 2, do a good job of monitoring the tunnel axis, ground settlement deformation, building deformation, etc., and effectively control the entire construction process according to the monitoring data.

3-3) Construction control under the river

The covering soil of the river is less than twice the diameter of the shield tunnel 1. Before advancing, the bridge is reinforced, and the protection of the bridge piles in the short distance is strengthened to prevent the river from flooding.

3-4) Construction measures for unknown obstacles

According to the interval geophysical report, analyze possible obstacles such as abandoned pile foundations, and roughly determine the location. During the propulsion process, attention should be paid to the change of the torque of the cutter head and the change of the thrust. When the torque increases, the total thrust increases, and the thrust of the four zones ABCD increases sharply.

3-5) Pipeline protection measures

According to the geological data and design documents provided by the owner, the pipelines along the section should be checked and implemented before construction.

3-6) During the whole construction process of cutting piles and crossing the river, the bentonite injection system is in a working state immediately. When the sudden change of earth pressure and the mismatch between the excavation footage and the unearthed amount (over-excavation) occur, the bentonite shall be injected into the soil bin immediately. The injection pressure should be higher than the earth pressure during excavation to ensure that the over-excavation area is fully filled with bentonite and reduce settlement.

4) Shield advancing parameter setting:

In the process of shield machine 1 passing through pile foundation 2, parameters such as propulsion speed and earth pressure must be strictly controlled to minimize the occurrence of overall displacement of pile foundation 2 itself. Shield 1 is 6m away from pile foundation 2. When advancing, the advancing speed must be slowed down, and the advancing speed should be controlled at 1cm/min. Unearthed; the shield machine cutter head is close to the pile foundation 2, and the advancing speed is further slowed down. Shield 1 excavation large-diameter pile foundation 2 takes "slow pushing speed, medium speed, soil pressure, inert grouting, and attitude control" as the core control technology.

4-1) Slow push speed

Shield 1 cutter head pile cutting is based on "grinding", and the cutter should be driven slowly and with a small depth of cut to grind concrete and steel bars. Considering that this project is more difficult and riskier than similar pile cutting projects in the past, a slower driving speed should be adopted and controlled at 1-3mm/min; if the thrust torque of shield 1 is too large during the pile cutting process, not only will the Affecting the safety of shield 1 itself, it will also generate a large force on the bridge piles, thereby affecting the safety of the bridge structure. Therefore, referring to the case experience, the thrust and torque control ranges are respectively 13000-18000kN and 2500-3500kN m.

4-2) Medium speed

In the case of a certain thrust speed, the rotating speed of the cutter head is relatively large, although the single cutting depth of the tool to the pile foundation 2 will be reduced, which is beneficial to reduce the thrust torque. The speed is inevitably large, which will cause the tool to be subjected to a large impact load when it contacts the pile foundation 2, which will easily lead to alloy cracking or even block collapse. Therefore, in order to take into account the dual needs of controlling the reasoning torque and protecting the tool, the speed of the cutter head should not be too large or too small, and a medium speed is appropriate, and the speed should be controlled at about 1.2 to 1.5 rpm.

4-3) Soil holding pressure

Soil holding pressure is the key to control bridge settlement. Different from the usual excavation, the disturbance caused by the pile cutting construction is mainly at the position of the cutter head, and the bearing capacity of the bridge piles and abutments comes from the support of the surrounding soil. Therefore, during the construction of the shield 1 cutting pile foundation 2, the Disturbance of the surrounding soil, especially to prevent excessive settlement and deformation of the soil, so the soil tank pressure setting should be appropriately increased when cutting piles. At the same time, during the dynamic excavation process, the earth pressure should be stably maintained at a high level. Specifically, it can be achieved by "sluggish push": first completely close the dump gate, and the shield machine will "sluggishly push" forward, and wait until the earth pressure rises to a higher level. After setting the earth pressure height, excavate manually, control the opening rate of the gate not to exceed 10%, close the gate immediately after the earth pressure drops to the set earth pressure, and continue to “stuff push”, and so on.

4-4) Inert grouting

After the cut piles of shield 1 pass, the cut upper residual piles will act on the grouting slurry behind the wall. For the type of slow grout, the amount of grouting can refer to the excavation of the shield in the same soil layer in the early stage, and then adjust it in time according to the monitoring data of bridge settlement. The amount of grouting and the point of grouting depend on the pressure value during grouting and monitoring data of formation deformation. The grouting must be assigned a special person responsible for making detailed records of the pressing position, pressing amount and pressure value, and making timely adjustments according to the monitoring information of formation deformation to ensure the construction quality of the grouting process.

4-5) Attitude control

In the process of cutting or grinding bridge piles by the shield 1 cutter head, the pile foundation 2 reacts on the cutter head, and the front face of the cutter head is easily subjected to uneven force, and the attitude control of the shield machine 1 is difficult. Since the shield machine 1 needs to continuously cut through multiple bridge piles, if the attitude control of the shield machine 1 is not good, it is likely that the cut off piles will directly act on the shield machine shell, and the safety of the pile ends to the segment will be further increased. Therefore, the control of shield 1 attitude, especially the vertical attitude, should be strengthened, and emergency correction should be avoided when correcting deviation. Under the condition that the frontal settlement of the shield machine 1 is well controlled, the shield machine 1 should be constructed at a balanced and uniform speed, and the attitude change of the shield machine 1 should not be too large, and the leading amount of the segment should be checked for each ring. When advancing, do not rush or rectify violently. Pay more attention to the gap between the segment and the shield shell. The variation of the oil pressure in the relative area gradually changes with the number of unearthed boxes and the stroke of the jack. The steady slope method and the gentle slope method are used to advance to reduce the shielding. The influence of the construction of structure 1; the posture of the shield machine during the pile cutting process is strictly controlled, and the cutter head and the pile body are in full contact during pile cutting, and there should be no skewness between the two.

4-6) Soil improvement on the front of the cutter head

Use of bentonite. Shield machine 1 needs to cut concrete. In order to ensure the normal excavation of shield machine 1, it is necessary to inject bentonite on the front of the cutter head of shield machine 1 at all times to improve the workability of the soil on the excavation surface, thereby reducing the torque of the cutter head to ensure the shield machine. 1. There is a balanced propulsion speed when crossing, and at the same time, the soil in the soil bin is improved, which helps the pile fragments to be smoothly discharged from the screw machine. When adding bentonite, the amount and pressure must be strictly controlled to avoid the formation of directional through-hole medium cracks in the soil under excessive injection of bentonite and high pressure, resulting in water seepage channels, which seriously affects the safety of the tunnel. According to the past construction experience and the related principles of bentonite or foaming agent, the injection volume of bentonite must match the excavation volume of the shield machine. Equipped with a handheld infrared thermometer, during the excavation process, every 30 cm of excavation, the temperature of the muck is measured once to judge the internal temperature of the soil bin.

4-7) Screw conveyor gate control and shield tail grease injection

Ensure that the front and rear gates are closed in time when the screw machine spout occurs, and the amount of spewing muck is minimized. Regularly check the shield tail grease pipeline and grease pump. Through daily excavation records, we can timely understand the working conditions of the shield tail grease injection system, predict failures as early as possible, and repair them in time. At the same time, good quality shield tail grease is selected to ensure the sealing performance of the shield tail (the pressure injection volume of each ring is 35kg. In case of special circumstances, the pressure injection volume of the shield tail grease can be increased according to the actual situation, and the pressure of the grease tank is 15~ 20bar).

5) Construction measures for crossing the river:

5-1) Strictly control the earth pressure balance of shield 1

Strictly control the construction parameters related to the balance pressure, prevent over-excavation and under-excavation, and minimize the fluctuation of the balance pressure.

5-2) Strictly control the propulsion speed of shield 1

When advancing, the speed should be controlled at 2-3cm/min, the construction should be balanced, the disturbance to the surrounding soil should be reduced, and a long pause and delay on the way should be avoided.

5-3) Strictly control the deviation correction amount of shield 1

When advancing, check and adjust the posture of each segment, adopt the steady slope method and the gentle slope method to advance, so that the shield machine 1 is advanced in a balanced and uniform speed, and the amount of deviation correction is strictly controlled to reduce the impact of the construction of the shield machine 1 on the ground.

5-4) Strictly control the amount of grouting and the quality of grouting

Ensure that the total amount of grouting in each ring is in place; ensure that during the process of shield 1 advancing each box of soil, the grout is injected evenly; the proportion of grout must meet the quality standards.

5-5) When necessary, add soil conditioner to the soil bin to ensure the water retention of the soil in the soil bin and prevent the river water from passing through.

6) Control technology after shield 1 crosses pile foundation 2:

After the shield tail of shield 1 is out of the pile foundation 2 area, secondary grouting shall be carried out for the tunnel in this area, and three or four times of grouting can be carried out if necessary. At the same time, grouting holes are added to the segment. On the premise of the original 6 grouting holes, another 10 grouting holes are added, so that the grouting can be carried out at multiple points and small pressure, and the effect of grouting is guaranteed. Through the secondary grouting, the gap between the tunnel and the reinforcement area can be replenished in time to further ensure that the ground subsidence in this area is controlled. The influence range of the shield machine cutting pile foundation 2 is the distance of the 35th ring, so the timely secondary grouting construction is adopted in this 35th ring. The amount of grouting is tentatively set at 1.5m ³ per ring, divided into 5 segment assembly holes for injection, and the amount of injection in each hole is 0.3m ³ .

The invention has the advantages of high stability, fast construction speed and the like, and at the same time, the construction quality can be guaranteed, and the application prospect of subsequent engineering construction is good.

Claims (6)

1. a construction method for silt soil layer shield cutting piles to cross the river, is characterized in that, comprises the following steps: 1) Material preparation: make preparations for the secondary grouting after the segment wall; overhaul the secondary grouting equipment in advance; Impact drill for grouting holes; prepare cement, water glass, check valve and hand hole plug for grouting; 2) Shield machine (1) Cutting pile foundation (2) Specific measures: pile cutting construction control: shield machine (1) Control soil pressure, cutter head torque, grouting pressure and excavation volume during the process of cutting pile foundation (2) Various important parameters; monitoring and control: arrange the measuring points to measure the initial value, before the shield (1) crosses the pile foundation (2) or after the shield (1) crosses the pile foundation (2), do the tunnel axis, ground settlement and deformation and monitoring of building deformation, the whole construction process is controlled according to the monitoring data; construction control under the river: when the overburden height of the river is less than twice the diameter of the shield (1), the bridge shall be reinforced before advancing, and the Protection of distance bridge piles and prevention of river water perfusion; construction measures for unidentified obstacles: analyze the location of obstacles according to the interval geophysical report, and pay attention to the changes of cutter head torque and thrust during the advancing process; pipeline protection measures: before construction The pipelines along the interval are checked and implemented; during the whole construction process of cutting piles and crossing the river, the bentonite injection system is in a working state. The injection pressure is higher than the earth pressure during excavation; 3) Shield tunnel (1) setting of propulsion parameters: during the process of shield tunnel (1) passing through the pile foundation (2), the thrust speed and earth pressure parameters are controlled; when the shield tunnel (1) approaches the pile foundation (2), Slow the advancing speed and add lubricant to the cutter head; when the cutter head of the shield machine (1) is close to the pile foundation (2), the advancing speed is slowed down; when the cutter head of the shield machine (1) cuts the pile, the cutter is ground at a slow pushing speed Cutting concrete and steel bars; under the condition of a certain pushing speed, the cutter head cuts piles at a medium speed; increase the soil tank pressure setting when cutting piles, during the dynamic excavation process, keep the soil pressure at a high level, and close the dump gate first , the shield (1) is pushed forward, and when the soil tank pressure rises to a higher pressure than the set soil tank pressure, the excavation is manually excavated, and the opening rate of the gate is controlled not to exceed 10%. Gate, continue to push, and so on; after the shield tunnel (1) cuts through the piles, select the type of grout with low strength and slow solidification. Data is adjusted; during grouting, the indentation position, indentation amount and pressure value are recorded in detail, and adjustments are made according to the monitoring information of formation deformation; The leading amount of the segment is checked by the ring; the steady slope method and the gentle slope method are used when advancing; the shield machine (1) The attitude control is performed during the pile cutting process, and the cutter head and the pile body are in full contact when the pile is cut, and there is no skew ;Injecting bentonite on the front of the cutter head of the shield (1) to improve the workability of the excavated surface soil, controlling the amount and pressure when adding the bentonite, and the injection amount of the bentonite and the excavation volume of the shield (1) match each other; Equipped with a handheld infrared thermometer to judge the internal temperature of the soil bin; close the front and rear gates when the screw machine spout occurs; regularly check the shield tail grease pipeline and grease pump, and select good quality shield tail grease; learn about the shield tail grease through daily excavation records The working condition of the injection system, predict the failure in advance, and repair it; 4) Construction measures for crossing the river: control the earth pressure balance of the shield (1); control the propelling speed of the shield (1); Adopt the steady slope method and the gentle slope method to advance, make the shield (1) advance at a balanced and uniform speed, control the deviation correction amount to reduce the impact of the shield (1) construction on the ground; control the synchronous grouting amount and the quality of the slurry; 5) Control technology after the shield (1) passes through the pile foundation (2): after the shield tail of the shield (1) falls out of the pile foundation (2) area, grouting is performed two to four times for the tunnel in this area. The amount is adjusted according to the monitoring data of land subsidence. 2. The construction method of silt ground shield cutting piles and crossing the river according to claim 1, it is characterized in that: before step 1), carry out shield (1) equipment inspection, check synchronous grouting system, foam injection system , Check the earth pressure balance system, check the shield tail grease injection system, check the hinged sealing system, check the drainage system in the tunnel, check the communication system. 3. The construction method of silt ground shield cutting piles and crossing the river according to claim 1, characterized in that: in the step 3), when the cutterhead of the shield (1) cuts the piles The concrete and steel bars are cut at a slow pushing speed of min, and the thrust and torque of the shield (1) are controlled to be 13000-18000 kN and 2500-3500 kN m, respectively. 4. The construction method of silt stratum shield cutting piles and crossing the river according to claim 1, characterized in that: in the step 3), under a certain pushing speed, the cutter head rotates at a medium speed of 1.2～1.5rpm Cut piles. 5 . The construction method for silt ground shield cutting piles to cross a river according to claim 1 , wherein: in the step 4), the propelling speed of the shield (1) is controlled at 2-3 cm/min. 6 . 6. The construction method of silt soil stratum shield cutting piles to cross the river according to claim 1, is characterized in that: in the described step 4), if necessary, add soil conditioner into the soil bin.