CN110524672A - Ventilation type large-diameter shield section of jurisdiction condenses pipe device and construction method - Google Patents

Abstract

A kind of ventilation type large-diameter shield section of jurisdiction condenses pipe device, and described device includes the condenser pipe being embedded in shield duct piece and the first, second, third temperature sensor for detecting concrete temperature；The two ends of the condensation tube assembly are respectively equipped with air inlet and air outlet；Air inlet connects Water cooled air conditioners；Air outlet connects exhaust fan.And provide a kind of construction method of ventilation type large-diameter shield section of jurisdiction condensation pipe device.The present invention efficiently solve large-diameter shield it is segment prefabricated when the aquation heat problem that generates, so that shield duct piece intensity is reached design requirement, guarantee section of jurisdiction quality.

Description

Air-cooled large-diameter shield segment condenser tube device and construction method

technical field

The invention relates to a large-volume concrete maintenance technology, and more specifically, relates to a shield segment condenser tube device and a construction method.

Background technique

In recent years, the development of shield tunneling has become more and more mature, and there are more and more large-diameter shield tunnels, and the required segment thickness has also increased. However, temperature cracks often appear during the prefabrication of large-diameter shield segments, because when the large-diameter shield segments are poured with concrete, a large amount of hydration heat will be released inside the concrete during the hardening process of the large-volume concrete, resulting in large temperature changes. The resulting temperature stress and shrinkage stress can easily lead to cracks in the structure. Therefore, how to effectively control the heat of hydration inside the concrete and avoid the occurrence of temperature cracks has become the focus and difficulty of segment prefabrication. At present, the commonly used treatment measures in engineering are mostly adjusting the concrete mix ratio, adjusting the temperature of concrete raw materials or performing steam curing, but these treatment measures have relatively large limitations, and cannot effectively solve the problem of large-volume shield segment prefabrication. The problem of hydration heat generated during concrete pouring is still prone to cracks, so that the performance of the segments cannot meet the design requirements.

Contents of the invention

Aiming at the deficiencies of the prior art, the present invention provides an air-cooled large-diameter shield segment condenser device and a construction method, the method is simple, the construction is convenient, and the construction effect is good, which can effectively solve the problem of large-diameter shield segment concrete The generated hydration heat problem makes the concrete strength meet the design requirements and ensures the quality of the segments.

To achieve the above object, the present invention provides the following technical solutions:

An air-cooled large-diameter shield segment condensation tube device, the device includes a condensation tube embedded in the shield segment and first, second, and third temperature sensors for detecting the temperature of concrete; the condensation An air inlet and an air outlet are respectively provided at the head and tail ends of the tube assembly; the air inlet is connected to a water-cooled air conditioner; and the air outlet is connected to an exhaust fan.

Further, the first temperature sensor is set at the middle of the shield segment, the second temperature sensor is set at the side of the shield segment close to the water inlet, and the third temperature sensor is set at the shield segment The pipe piece is on the side of the water outlet.

Still further, the first temperature sensor is used to collect temperature change data during the hardening process of the concrete in the middle of the shield segment, and the second and third temperature sensors are used to collect temperature change data on the surface of the segment. By transmitting the temperature data to the background control system, the staff can change the power of the fan according to the data displayed in the background, and control the flow and velocity of the cold air in the condensation pipe, thereby effectively solving the problem of hydration heat inside the concrete.

The top view structure of the condensation pipe assembly is arranged in an S-shape.

The condenser tube assembly is arranged in a single layer.

In the section, each condensation pipe is set in the middle of the shield segment.

According to the size and type of shield segments, the arrangement of condensation pipes can be divided into circumferential arrangement and axial arrangement. The capping block adopts axial arrangement, and the standard block adopts circumferential arrangement.

The condensing equipment uses air for heat exchange, and its cooling effect depends on the air cooled by water-cooled air conditioners. The air is pumped out of the condenser tube.

A construction method of an air-cooled large-diameter shield segment condenser tube device, the construction method comprising the following steps:

Step 1. Condensation pipe and temperature measurement point embedding design calculation: select a suitable diameter condensation pipe according to the actual situation of the project, and determine the embedding position of the temperature sensor. The diameter of the condensation pipe is selected according to the thickness of the shield segment, and the thickness is greater than or equal to 0.4m and less than 0.6m. Condenser pipe; the thickness is greater than or equal to 0.6m and less than 0.8m Condenser pipe; thickness greater than 0.8m selection the condensation tube;

Step 2. Material processing: according to the value determined in the previous step, position and lay out the wires on the flat site, and process the steel bars and condensation pipes;

Step 3. Installation of temperature measurement facilities and condensation pipes: making steel cages, installing condensation pipes and temperature sensors at certain positions;

Step 4. Mold and equipment installation inspection: hoist the reinforcement cage into the mold, install and check the relevant equipment, including the airtightness inspection of the condensation pipe, the inspection of the temperature measuring equipment, the inspection of the fan equipment, and the inspection of the reinforcement cage;

Step five, concrete pouring and condensing equipment start;

Step 6. Dynamic temperature control: dynamically adjust the cooling air rate according to the feedback data of the temperature sensor, and control the concrete temperature;

Step 7, Condenser grouting.

The beneficial effects of the present invention are mainly manifested in: (1), the method is simple, the design is reasonable, the operation is convenient, and the actual engineering operation is practical; (2), the actual temperature control process relies on the real-time feedback of the temperature sensor, and the degree of automation is high. The cooling efficiency can be improved; (3), the practical value is high and the use effect is good, compared with the existing cooling method, the efficiency is high, and the probability of large cracks is greatly reduced; (4), the application range is wide, and it can be effectively applied to various Shield segments of various sizes. (5) Compared with the traditional condensing device, the present invention uses air for cooling, which greatly reduces engineering water consumption, saves water resources, and is environmentally friendly. At the same time, it saves the excavation of the water storage tank and cooling pool of the traditional condensing device, and improves the economic benefits of the project. .

Description of drawings

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

Figure 2 is a schematic diagram of shield segment assembly.

Fig. 3 is a schematic diagram of a condensing device for a shield segment connection block.

Fig. 4 is a schematic diagram of the circumferential longitudinal section of the condensation tube of the shield segment connection block.

Fig. 5 is a schematic diagram of an axial longitudinal section of the condenser segment connecting block.

Fig. 6 is a schematic diagram of the condensing device for the capping block of the shield segment.

Fig. 7 is a schematic diagram of the radial longitudinal section of the condensation tube of the shield segment capping block.

Fig. 8 is a schematic diagram of a bent joint of a condensation pipe.

Explanation of reference signs

1—shield segment capping block; 2—shield segment connection block; 2—condensation pipe; 4—air inlet; 5—air outlet; 6—water-cooled air conditioner; 7—exhauster fan; 8—second temperature sensor; 9—first temperature sensor; 10—third temperature sensor; 11—bending joint; 12—mold.

Detailed ways

In order to make the object, technical solution and advantages of the present invention clearer, the present invention will be further described below in conjunction with the accompanying drawings.

Referring to Figures 1 to 8, an air-cooled large-diameter shield segment condenser tube device includes a condenser tube 2 embedded in the shield segment and first, second, and The third temperature sensor; the head and tail ends of the condensation pipe assembly are respectively provided with an air inlet 4 and an air outlet 5; the air inlet 4 is connected to the water-cooled air conditioner 6; the air outlet 5 is connected to the exhaust fan 7.

Further, the first temperature sensor 9 is set at the middle of the shield segment, the second temperature sensor 8 is set at the side of the shield segment close to the water inlet, and the third temperature sensor 10 is set at the The shield segment is on the side of the water outlet.

Still further, the first temperature sensor is used to collect temperature change data during the hardening process of the concrete in the middle of the shield segment, and the second and third temperature sensors are used to collect temperature change data on the surface of the segment. By transmitting the temperature data to the background control system, the staff can change the power of the fan according to the data displayed in the background, and control the flow and velocity of the cold air in the condensation pipe, thereby effectively solving the problem of hydration heat inside the concrete.

The top view structure of the condensation pipe assembly is arranged in an S-shape.

The condenser tube assembly is arranged in a single layer.

In the section, each condensation pipe is set in the middle of the shield segment.

According to the size and type of shield segments, the arrangement of condensation pipes can be divided into circumferential arrangement and axial arrangement. The capping block adopts axial arrangement, and the standard block adopts circumferential arrangement.

The condensing equipment uses air for heat exchange, and its cooling effect depends on the air cooled by water-cooled air conditioners. The air is pumped out of the condenser tube.

As shown in Figure 1, the air-cooled shield segment condenser tube device and construction method process flow. The relative positions of the condensing pipe, the temperature detector and the shield segment are shown in Figure 2, the condensing pipe is buried inside the segment, the first temperature sensor is located in the middle of the shield segment, and the second temperature sensor is located in the middle of the shield segment. On the water inlet side of the shield segment, the third temperature sensor is arranged on the water outlet side of the shield segment. The axial section of the condensation pipe device is shown in FIG. 4 , and two adjacent parallel condensation pipes are connected by a curved joint 11 .

The specific process is as follows:

Take a shield segment with a width of 1.8m, a thickness of 0.55m, and a segment diameter of 11.6m as an example.

1. Condenser pipe and temperature measuring point embedding calculation:

As shown in Figure 3, Figure 4, and Figure 5, for the standard block, the condenser pipes are arranged in a circumferential direction, and the For steel pipes with a thickness of 3mm, the distance between parallel pipes is 400mm, and the arrangement starts at 200mm away from the short side surface of the segment in the transverse direction, and starts at 300mm away from the long side surface of the segment in the longitudinal direction. The first temperature sensor is buried at the center of the segment, and the second and third temperature sensors are buried at 150mm from the respective surfaces. The air inlet and outlet should lead to more than 300mm from the concrete surface to facilitate subsequent equipment installation.

As shown in Figure 6 and Figure 7, for the capping block, the condensation pipe is arranged axially, and the For steel pipes with a thickness of 3mm, the distance between parallel pipes is 400mm, and the arrangement starts at 200mm away from the short side surface of the segment longitudinally and 300mm away from the long side surface of the segment transversely. The first temperature sensor is buried at the center of the segment, and the second and third temperature sensors are buried at 150mm from the respective surfaces. The air inlet and outlet should lead to more than 300mm from the concrete surface to facilitate subsequent equipment installation.

2. Positioning and setting out, material processing: according to the value determined in the previous step, position and set out on the flat site, and process steel bars and condensation pipes. Due to the long length of the condensation pipe, be careful not to damage the steel pipe during processing and handling, and pay attention to the safety of the construction personnel.

3. Installation of temperature measuring facilities and condenser pipes:

Make steel cages, install condensation pipes and temperature sensors at certain locations. The following points should be paid attention to during installation:

3.1) When installing the sensor, the sensor at the contact point with the steel bar must be isolated with insulating material in order to accurately monitor the internal temperature change of the concrete.

3.2) Install the condensing pipe while binding the reinforcement cage. The condensing pipe should be staggered from the main reinforcement during installation. When it is difficult to stagger the local segments, the position of the condensing pipe should be moved appropriately. The condensation pipe should be firmly bound to the steel frame or the erection steel bar to prevent the condensation pipe from being deformed or falling off during the concrete pouring process.

3.3) Sensors are numbered before installation. After the sensor is installed, a test adjustment must be made.

4. Mold and equipment installation inspection: hoist the reinforcement cage into the mold 12, install and inspect related equipment, including the airtightness inspection of the condensation pipe, the temperature measurement equipment inspection, the fan equipment inspection, and the reinforcement cage inspection. Specifically, the air supply device is Rundongfang RDF-18A air cooler, which is connected to the air inlet; the exhaust device is a 4-72C centrifugal fan, which is connected to the air outlet.

5. Concrete pouring and condensing equipment start-up:

5.1) Concrete preparation

To prepare concrete suitable for this project, pay attention to the use of cement with low heat of hydration.

5.2) Pouring concrete

Vibrate and tamp while pouring concrete, and be careful not to damage the condensation pipe and temperature sensor when vibrating. When pouring concrete, the concrete must not directly impact the temperature sensor to prevent the sensor from being damaged.

5.3) ventilation cooling

When the concrete is covered and vibrated, wait for 10 hours and start ventilating in the condensation pipe of this layer. The flow of cooling air is controlled at 45-50m ³ /min. Isolation measures are set up near the air inlet and outlet. Unrelated personnel are strictly prohibited from approaching, and operators should pay attention to safety.

6. Dynamic temperature control:

According to the temperature sensor feedback data, the cooling air speed is dynamically adjusted to control the concrete temperature.

6.1) Data Collection

In this project, the temperature sensor buried in the segment is connected with the computer, which can accurately control the temperature difference of the mass concrete, grasp the temperature change at different depths and the development law of the temperature difference in the early and middle stages of construction. The temperature value fed back by the first temperature sensor is taken as value 1; the average value of the temperature value fed back by the second temperature sensor and the temperature value fed back by the third temperature sensor is taken as value 2.

6.2) Data comparison

Comparing the value 1 with the value 2, when the value difference exceeds 6°C, that is, when the concrete core temperature is too high, the computer sends a signal 1 to the high-pressure exhaust fan; when the value difference is lower than another set value, that is, when the concrete core temperature drops , the computer sends a signal 2 to the high-pressure exhaust fan.

6.3) Dynamic Control

When the multi-stage fan receives signal 1, it increases the operating power of the fan to speed up the cooling air flow; when it receives signal 2, it reduces the operating power of the fan; when there is no signal input, it maintains the current power. After the power of the fan is changed, the data collection steps are repeated. This cycle is used to achieve large flow ventilation at high temperature, low flow ventilation or stop ventilation at low temperature, and effectively reduce the temperature difference between the inside and outside of the concrete. Under special circumstances, the power of the fan can be directly controlled manually to ensure that the cooling rate is within a reasonable range.

6.4) Precautions

①The temperature control and temperature measurement records must be guaranteed to be carried out continuously, and someone must be on-site to monitor the temperature during dynamic control.

②The temperature measurement data must be carefully recorded and the results reported in time, so as to implement more timely maintenance measures for the temperature control of the concrete.

③ The difference between the atmospheric temperature and the surface temperature of the concrete should be controlled within 10°C; the cooling rate of the concrete should generally not exceed 2°C/d

7. Condenser pipe grouting:

After the concrete strength meets the standard requirements, remove the water-cooled air conditioner, exhaust fan and other equipment, take out the segments, and immediately fill the condenser pipe with cement slurry. The compressive strength of the cement slurry should not be less than the statistical concrete strength.

To sum up, the solution of the present invention is suitable for controlling temperature cracks in shield segments. The shield segment condenser tube device and construction method adopted in the present invention have the advantages of convenient operation, environmental protection and the like. The present invention is disclosed above with preferred embodiments, but it is not intended to limit the protection scope of the present invention. Due to the widespread occurrence of cracks in the shield segment during construction, most of the shield segment can adopt the present invention, or apply the present invention with a little modification and modification. The protection scope of the present invention should be determined by the claims.

Claims (9)

1. An air-cooled large-diameter shield segment condensation tube device is characterized in that, the device includes a condensation tube embedded in the shield segment and the first, second, and third tubes for detecting the concrete temperature A temperature sensor; an air inlet and an air outlet are respectively provided at the head and tail of the condensing pipe assembly; the air inlet is connected to a water-cooled air conditioner; the air outlet is connected to an exhaust fan. 2. The air-cooled large-diameter shield segment condenser tube device according to claim 1, wherein the first temperature sensor is located at the middle of the shield segment, and the second temperature sensor is located at the middle of the shield segment. The shield segment is on the side near the water inlet, and the third temperature sensor is arranged on the side of the shield segment near the water outlet. 3. The air-cooled large-diameter shield segment condenser tube device as claimed in claim 2, wherein the first temperature sensor is used to collect temperature change data during the hardening process of the concrete in the middle of the shield segment, and the first The second and third temperature sensors are used to collect temperature change data on the surface of the segment. By transmitting the temperature data to the background control system, the staff can change the power of the fan according to the data displayed in the background, and control the flow and velocity of the cold air in the condensation pipe, thereby effectively solving the problem of hydration heat inside the concrete. 4. The air-cooled large-diameter shield segment condensing tube device according to any one of claims 1 to 3, wherein the condensing tube assembly has an S-shaped meandering structure in a top view. 5. The air-cooled large-diameter shield segment condensing tube device according to claim 4, wherein the condensing tube assembly is arranged in a single layer. 6. The air-cooled large-diameter shield segment condenser tube device as claimed in claim 4, characterized in that, in the section, each condenser tube is arranged in the middle of the shield segment. 7. The air-cooled large-diameter shield segment condenser tube device according to any one of claims 1-3, characterized in that the arrangement of the condenser tubes is divided into circumferential arrangement and axial arrangement according to the size and type of the shield segment , the capping blocks are arranged in the axial direction, and the standard blocks are arranged in the circumferential direction. 8. The air-cooled large-diameter shield segment condensing tube device according to any one of claims 1-3, wherein the condensing equipment uses air for heat exchange, and its cooling effect depends on the air cooled by the water-cooled air conditioner , the cold air in the condenser tube is air at normal temperature, which is cooled by a high-power water-cooled air conditioner and sent into the condenser tube. At the same time, the air after heat exchange is drawn out of the condenser tube by a high-pressure exhaust fan. 9. A construction method of an air-cooled large-diameter shield segment condenser tube device as claimed in claim 1, wherein said construction method comprises the following steps: Step 1. Condensation pipe and temperature measurement point embedding design calculation: select a suitable diameter condensation pipe according to the actual situation of the project, and determine the embedding position of the temperature sensor. The diameter of the condensation pipe is selected according to the thickness of the shield segment, and the thickness is greater than or equal to 0.4m and less than 0.6m. Condenser pipe; the thickness is greater than or equal to 0.6m and less than 0.8m Condenser pipe; thickness greater than 0.8m selection the condensation tube; Step 2. Material processing: according to the value determined in the previous step, position and lay out the wires on the flat site, and process the steel bars and condensation pipes; Step 3. Installation of temperature measurement facilities and condensation pipes: making steel cages, installing condensation pipes and temperature sensors at certain positions; Step 4. Mold and equipment installation inspection: hoist the reinforcement cage into the mold, install and check the relevant equipment, including the airtightness inspection of the condensation pipe, the inspection of the temperature measuring equipment, the inspection of the fan equipment, and the inspection of the reinforcement cage; Step five, concrete pouring and condensing equipment start; Step 6. Dynamic temperature control: dynamically adjust the cooling air rate according to the feedback data of the temperature sensor, and control the concrete temperature; Step 7, Condenser grouting.