Cement mixing pile for monitoring cement content in real time

Abstract

This invention discloses a cement mixing pile for real-time monitoring of cement content. It features a support frame, a rotary actuator fixedly mounted on the support frame, a rotary drill rod with helical blades, an internally insulated monitoring box, a cement content monitoring mechanism, a DC power supply, and a signal processing module. The rotary actuator drives the rotary drill rod to rotate. The monitoring box is fixedly mounted on the rotary drill rod and has openings on both sides along the rotation direction of the drill rod. The DC power supply is fixedly mounted on the rotary actuator and provides voltage to the inner and outer ends of the medium flowing through the monitoring box via the cement content monitoring mechanism. The cement content monitoring mechanism transmits the current signal generated after the medium in the monitoring box is energized to the signal processing module. The signal processing module obtains the cement content in the added cement slurry based on the current signal. The advantages are a simple overall structure and the ability to obtain the cement content in newly added cement slurry in real time.

Description

Technical Field

[0001] This invention relates to a cement mixing pile, and more particularly to a cement mixing pile with real-time monitoring of cement content. Background Technology

[0002] Cement mixing piles are suitable for reinforcing soft soils with abundant groundwater. They are widely used in water-stop curtains, soil reinforcement, and shallow foundation composite foundation reinforcement for building basements, municipal subways, and other engineering projects. The cement content per unit volume of soil is determined by the engineering design and specified in the construction drawings. During construction, a long screw with spiral blades is used to penetrate deep into the soil for mixing. At the same time, cement slurry is sprayed from the tip of the long screw to evenly spread in the soil, forming columnar cement-soil piles. Accurate control of both the actual cement content per unit volume of cement-soil and the degree of mixing uniformity is essential and directly affects the quality of the cement-soil piles.

[0003] The main types of construction machinery for cement mixing piles are single-axis, double-axis, and triple-axis mixing equipment. The common feature of the construction mixing behavior is that the soil is cut and broken up and mixed with the injected cement slurry. During the operation, the speed of the drill rod moving up and down during the mixing process is mainly controlled by humans and it is difficult to move at a uniform speed. The concentration of cement slurry and the amount of grouting are difficult to control precisely by humans. Therefore, since its inception, the construction quality of cement mixing piles has been difficult to control and has not been effectively solved.

[0004] Currently, the quality assessment of cement mixing piles is limited to drilling and sampling for pressure testing after the cement and soil have hardened. If the construction quality is found to be substandard, additional piles need to be added, and there is no other way. This measure is labor-intensive, time-consuming, increases project costs, and wastes resources. Therefore, the current quality inspection of cement mixing piles is a post-event activity, and its role is very passive and reactive. Summary of the Invention

[0005] The technical problem to be solved by the present invention is to provide a cement mixing pile with simple structure and convenient installation for real-time monitoring of cement content, which can obtain the cement content in newly added cement slurry in real time.

[0006] The technical solution adopted by the present invention to solve the above-mentioned technical problems is as follows: a cement mixing pile for real-time monitoring of cement content, comprising a support frame, a rotary actuator fixedly mounted on the support frame, a rotary drill rod with helical blades, an internally insulated monitoring box, a cement content monitoring mechanism, a DC power supply, and a signal processing module. The rotary actuator drives the rotary drill rod to rotate. The monitoring box is fixedly mounted on the rotary drill rod and has openings on both sides along the rotation direction of the rotary drill rod. The DC power supply is fixedly mounted on the rotary actuator and is used to provide voltage to the inner and outer ends of the medium flowing through the monitoring box through the cement content monitoring mechanism. The cement content monitoring mechanism is used to transmit the current signal generated after the medium in the monitoring box is energized to the signal processing module. The signal processing module is used to obtain the cement content in the added cement slurry based on the current signal.

[0007] The cement content monitoring mechanism includes a positive probe, a positive support, a negative probe, a negative support, a lead wire conduit, and a brush connection mechanism. The positive probe is fixedly mounted inside the monitoring box at the inner end of the rotating drill rod along the radial direction via the positive support. The negative probe is fixedly mounted inside the monitoring box at the outer end of the rotating drill rod along the radial direction via the negative support. The lead wire conduit passes through the spiral blade from top to bottom and is fixedly connected to the side wall of the rotating drill rod. The positive probe is electrically connected to the positive terminal of the DC power supply via a positive lead wire passing through the lead wire conduit and the brush connection mechanism. The negative probe is electrically connected to the negative terminal of the DC power supply via a negative lead wire passing through the lead wire conduit and the brush connection mechanism.

[0008] The brush connection mechanism includes a positive brush, a negative brush, an annular positive brush holder, and an annular negative brush holder. The bottom of the rotary actuator has an upwardly recessed connecting cavity. The positive and negative brushes are respectively fixedly mounted on the cavity wall of the connecting cavity. The positive brush is electrically connected to the positive terminal of the DC power supply, and the negative brush is electrically connected to the negative terminal of the DC power supply. An annular insulating mounting base is fixedly sleeved on the upper circumference of the rotary drill rod. The annular positive and negative brush holders are spaced apart from top to bottom and fixedly arranged around the annular insulating mounting base. The annular positive brush holder and the positive brush are in electrical sliding contact, and the annular negative brush holder and the negative brush are in electrical sliding contact. The upper end of the positive lead passes through the annular insulating mounting base from the inside to the outside and is electrically connected to the annular positive brush holder. The upper end of the negative lead is electrically connected to the annular negative brush holder.

[0009] The signal processing module includes a current detection module, a signal transmission module, and a cement content acquisition module. The current detection module amplifies the current signal and converts it into a digital signal, which is then transmitted to the cement content acquisition module via the signal transmission module. The cement content acquisition module has a pre-stored conductivity-hydroxide ion content lookup table. The cement content acquisition module obtains the first conductivity before adding cement slurry and the second conductivity after adding cement slurry based on the digital signal. It then matches the first conductivity with the conductivity-hydroxide ion content lookup table to obtain the corresponding first cement content, and simultaneously matches the second conductivity with the conductivity-hydroxide ion content lookup table to obtain the corresponding second cement content. The cement content acquisition module subtracts the second cement content from the first cement content to obtain the cement content in the added cement slurry. The cement content monitoring agency transmits the current signal of the medium in the monitoring box before and after the addition of cement slurry to the current detection module. The current detection module amplifies and converts the two current signals into digital signals, which are then sent to the cement content acquisition module via the signal transmission module. The cement content acquisition module obtains the resistance value of the medium in the monitoring box before and after the addition of cement slurry based on the digital signals, calculates the corresponding conductivity, and then looks up the conductivity in a pre-stored conductivity-hydroxide ion content lookup table to obtain the corresponding hydroxide ion content. Finally, the cement content before and after the addition of cement slurry is calculated based on the obtained hydroxide ion content, and the difference between the two is the cement content in the cement slurry added. The current detection module samples the current through a sampling resistor, amplifies the current, and converts it into a digital signal. This circuit structure is a commonly used conventional circuit structure. The signal transmission module generally uses wireless transmission to achieve long-distance transmission, allowing data to be viewed remotely on monitoring terminals such as computers or mobile phones.

[0010] Compared with existing technologies, the advantages of this invention are that it provides voltage to the inner and outer ends of the medium flowing through the monitoring box via a DC power supply and a cement content monitoring mechanism. The signal processing module then acquires the current signal of the medium before and after the addition of cement slurry. Based on the current signal, the resistance and conductivity of the monitored medium can be obtained. Since conductivity and hydroxide ion content have a fixed conversion relationship, the actual hydroxide ion content can be obtained based on this relationship. Because the change in hydroxide ions is entirely due to the cement slurry added, the cement slurry content before and after the addition of cement can be obtained through molecular formula conversion. The difference between the two is the newly added cement slurry content. The overall structure is simple and easy to install, requiring minimal modification to existing structures. It can acquire the cement content in the newly added cement slurry in real time, thereby accurately controlling the subsequent cement slurry concentration and grouting volume. It also issues an alarm promptly when insufficient cement is detected, ensuring high construction quality. Attached Figure Description

[0011] Figure 1 This is a schematic diagram of the overall structure of the present invention;

[0012] Figure 2 This is a partial structural schematic diagram of the present invention;

[0013] Figure 3 This is a partial internal structural diagram of the present invention;

[0014] Figure 4 This is a block diagram illustrating the signal control principle of the present invention. Implementation

[0015] The present invention will be further described in detail below with reference to the accompanying drawings and embodiments.

[0016] A cement mixing pile for real-time monitoring of cement content includes a support frame 1, a rotary actuator 2 fixedly mounted on the support frame 1, a rotary drill rod 3 with helical blades 31, an internally insulated monitoring box 4, a cement content monitoring mechanism, a DC power supply 5, and a signal processing module. The rotary actuator 2 drives the rotary drill rod 3 to rotate. The monitoring box 4 is fixedly mounted on the rotary drill rod 3 and has openings on both sides along the rotation direction of the rotary drill rod 3. The DC power supply 5 is fixedly mounted on the rotary actuator 2 and is used to provide voltage to the inner and outer ends of the medium flowing through the monitoring box 4 via the cement content monitoring mechanism. The current signal generated after the medium inside the monitoring box 4 is energized is transmitted to the signal processing module. The signal processing module is used to obtain the cement content in the added cement slurry based on the current signal. The cement content monitoring mechanism includes a positive probe 61, a positive support 62, a negative probe 63, a negative support 64, a lead wire conduit 65, and a brush connection mechanism. The positive probe 61 is fixedly installed inside the monitoring box 4 at the inner end of the rotating drill rod 3 along the radial direction through the positive support 62. The negative probe 63 is fixedly installed inside the monitoring box 4 at the outer end of the rotating drill rod 3 along the radial direction through the negative support 64. The lead wire conduit 65 passes through the spiral blade 3 from top to bottom. 1. It is fixedly connected to the side wall of the rotary drill rod 3. The positive probe 61 is electrically connected to the positive terminal of the DC power supply 5 through the positive lead 66 passing through the lead conduit 65 and the brush connection mechanism. The negative probe 63 is electrically connected to the negative terminal of the DC power supply 5 through the negative lead 67 passing through the lead conduit 65 and the brush connection mechanism. The brush connection mechanism includes a positive brush 71, a negative brush 72, an annular positive brush holder 73, and an annular negative brush holder 74. The bottom of the rotary driver 2 is recessed upward to provide a connecting cavity 21. The positive brush 71 and the negative brush 72 are respectively fixedly installed on the cavity wall of the connecting cavity 21. The positive brush 71 is connected to the DC power supply 5 through the lead conduit 65 and the brush connection mechanism. The positive terminal of the power supply 5 is electrically connected, and the negative terminal brush 72 is electrically connected to the negative terminal of the DC power supply 5. An annular insulating mounting base 75 is fixedly sleeved on the upper circumference of the rotary drill rod 3. The annular positive terminal brush holder 73 and the annular negative terminal brush holder 74 are respectively distributed from top to bottom and fixedly arranged around the annular insulating mounting base 75. The annular positive terminal brush holder 73 is electrically sliding in contact with the positive terminal brush 71, and the annular negative terminal brush holder 74 is electrically sliding in contact with the negative terminal brush 72. The upper end of the positive terminal lead 66 passes through the annular insulating mounting base 75 from the inside to the outside and is electrically connected to the annular positive terminal brush holder 73. The upper end of the negative terminal lead 67 is electrically connected to the annular negative terminal brush holder 74.

[0017] The signal processing module includes a current detection module 81, a signal transmission module 82, and a cement content acquisition module 83. The current detection module 81 amplifies the current signal and converts it into a digital signal, which is then transmitted to the cement content acquisition module 83 via the signal transmission module 82. The cement content acquisition module 83 has a pre-stored conductivity-hydroxide ion content lookup table. The cement content acquisition module 83 acquires the first conductivity before adding cement slurry and the second conductivity after adding cement slurry based on the digital signal. It then matches the first conductivity with the conductivity-hydroxide ion content lookup table to obtain the corresponding first cement content. Simultaneously, it matches the second conductivity with the conductivity-hydroxide ion content lookup table to obtain the corresponding second cement content. The cement content acquisition module 83 subtracts the two second cement contents to obtain the cement content in the added cement slurry.

[0018] In the above embodiments, the cement content acquisition module 83 acquires the resistance value of the medium in the monitoring box 4 before and after the cement slurry is added based on the digital signal, and calculates the corresponding conductivity. Then, it searches for the corresponding hydroxide ion content in a pre-stored conductivity-hydroxide ion content lookup table. Finally, it calculates the cement content before and after the cement slurry is added based on the obtained hydroxide ion content. The difference between the two is the cement content in the cement slurry added this time. The theoretical basis for this calculation result is based on the alkaline characteristics of cement, the conductivity of hydroxide ions, and the variable resistance characteristics of cement soil.

[0019] The alkaline characteristics of cement are as follows: Cement used for cement mixing piles is mainly ordinary Portland cement. The main chemical components of this cement are a mixture of tricalcium silicate, dicalcium silicate, and tricalcium aluminate. The mixture has a high proportion of calcium oxide, which turns into calcium hydroxide upon contact with water and ionizes to release a high concentration of hydroxide ions. Therefore, cement has strong alkaline characteristics. In reality, the mass of calcium oxide in a specific type of cement is a fixed value, and therefore the mass of hydroxide ions is also a fixed value. Thus, once the hydroxide ion content is obtained, the corresponding cement mass can be obtained through a fixed conversion formula.

[0020] The conductivity of hydroxide ions is as follows: Scientific experiments have proven that under the same objective conditions, i.e., the same ion concentration, hydroxide ions contribute much more to conductivity than other ions. For example, relevant literature has a table describing the conductivity of hydroxide ions. The concentration of hydroxide ions is quite sensitive to conductivity. As the ion concentration increases, the conductivity increases proportionally. During the mixing of cement and soil, as the cement paste content increases, the hydroxide ion concentration increases, and the conductivity of the cement and soil will inevitably increase rapidly.

[0021] The resistivity characteristics of cement-soil are as follows: when cement slurry is added and mixed evenly, the amount of cement determines the concentration of hydroxide ions per unit volume of soil. The concentration of hydroxide ions increases the conductivity of cement-soil, so cement-soil exhibits relatively sensitive resistivity characteristics during the mixing process.

Claims

1. A cement mixing pile for real-time monitoring of cement content, characterized in that... The system includes a support frame, a rotary actuator fixedly mounted on the support frame, a rotary drill rod with helical blades, an internally insulated monitoring box, a cement content monitoring mechanism, a DC power supply, and a signal processing module. The rotary actuator drives the rotary drill rod to rotate. The monitoring box is fixedly mounted on the rotary drill rod and has openings on both sides along the rotation direction of the rotary drill rod. The DC power supply is fixedly mounted on the rotary actuator and is used to provide voltage to the inner and outer ends of the medium flowing through the monitoring box via the cement content monitoring mechanism. The cement content monitoring mechanism is used to transmit the current signal generated after the medium in the monitoring box is energized to the signal processing module. The signal processing module is used to obtain the cement content in the added cement slurry based on the current signal. The cement content monitoring mechanism includes a positive probe, a positive support, a negative probe, a negative support, a lead wire conduit, and a brush connection mechanism. The positive probe is fixedly installed inside the monitoring box at the inner end of the rotating drill rod along the radial direction via the positive support. The negative probe is fixedly installed inside the monitoring box at the outer end of the rotating drill rod along the radial direction via the negative support. The lead wire conduit passes through the spiral blade from top to bottom and is fixedly connected to the side wall of the rotating drill rod. The positive probe is electrically connected to the positive terminal of the DC power supply via a positive lead wire passing through the lead wire conduit and the brush connection mechanism. The negative probe is electrically connected to the negative terminal of the DC power supply via a negative lead wire passing through the lead wire conduit and the brush connection mechanism. The brush connection mechanism includes a positive brush, a negative brush, an annular positive brush holder, and an annular negative brush holder. The bottom of the rotary actuator has an upwardly recessed connecting cavity. The positive and negative brushes are respectively fixedly mounted on the cavity wall of the connecting cavity. The positive brush is electrically connected to the positive terminal of the DC power supply, and the negative brush is electrically connected to the negative terminal of the DC power supply. An annular insulating mounting base is fixedly sleeved on the upper circumference of the rotary drill rod. The annular positive and negative brush holders are spaced apart from top to bottom and fixedly arranged around the annular insulating mounting base. The annular positive brush holder and the positive brush are in electrical sliding contact, and the annular negative brush holder and the negative brush are in electrical sliding contact. The upper end of the positive lead passes through the annular insulating mounting base from the inside to the outside and is electrically connected to the annular positive brush holder. The upper end of the negative lead is electrically connected to the annular negative brush holder.

2. A cement mixing pile for real-time monitoring of cement content according to claim 1, characterized in that... The signal processing module includes a current detection module, a signal transmission module, and a cement content acquisition module. The current detection module amplifies the current signal and converts it into a digital signal, which is then transmitted to the cement content acquisition module via the signal transmission module. The cement content acquisition module has a pre-stored conductivity-hydroxide ion content lookup table. The cement content acquisition module obtains the first conductivity before adding cement slurry and the second conductivity after adding cement slurry based on the digital signal. It then matches the first conductivity with the conductivity-hydroxide ion content lookup table to obtain the corresponding first cement content, and simultaneously matches the second conductivity with the conductivity-hydroxide ion content lookup table to obtain the corresponding second cement content. The cement content acquisition module subtracts the second cement content from the first cement content to obtain the cement content in the added cement slurry.

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