CN209958323U - Carbonization process monitoring device for magnesia cement cured soft soil - Google Patents

Abstract

The utility model discloses a carbonization process monitoring devices of magnesia cement solidification weak soil, the device mainly includes: carbon dioxide gas pitcher, cylinder bucket, sensor, lye tank and data acquisition device. The monitoring device can monitor the change rule of pore pressure, temperature and water content at different earth pillar depths along with the initial conditions in real time through the combination of the parts, predict the carbonization process of the magnesium oxide solidified soft soil, and verify the prediction result by combining the pH value and conductivity results of soil samples at different depths. The device is also specially provided with an alkali liquor tank, so that waste gas and waste liquor in the magnesium oxide carbonized soil column can be effectively absorbed, and environmental pollution is avoided. Through the utility model discloses implement, can confirm best ventilation pressure, initial moisture content and the compactedness of magnesia cement solidification weak soil, provide profitable guidance for the carbonization reinforcement of soft soil foundation low carbon environmental protection and the reasonable high-efficient utilization of magnesia-carbon dioxide curing agent.

Description

Carbonization process monitoring device for magnesia cement cured soft soil

Technical Field

The utility model discloses a carbonization process monitoring devices of magnesia cement solidification weak soil belongs to the device class in weak soil solidification processing field.

Background

In civil engineering construction, it is often necessary to reinforce soft soil foundations having low strength, high compressibility and poor permeability, and common treatment methods include a replacement and filling method, a cement/lime mixing pile method, and the like. The replacement method has large treatment project amount and high manufacturing cost, and is suitable for shallow foundations; the cement/lime soil mixing pile method is widely applied due to the advantages of high construction speed, small disturbance, low cost and the like, but the strength of the cement/lime soil mixing pile is slowly increased, and the used curing materials, namely cement and lime, have high energy consumption, large carbon dioxide emission and serious environmental pollution in the production process. Therefore, the inventor sets out a carbonization mixing pile method and an integral carbonization method which adopt magnesium oxide to reinforce the soft soil foundation, and applies a series of invention patents, and the similar characteristics and beneficial effects of the invention patents are as follows: active oxides are used as soil curing agents, and carbon dioxide is introduced for carbonization so as to realize rapid reinforcement of weak foundation soil. Compared with cement solidified soil or a traditional stirring and transferring method, the method has the characteristics of high reinforcing speed, high strength and good environmental benefit, and accords with the development trend of green construction of civil engineering.

In the foundation treatment method, the inventor has proposed a carbonization mixing pile and a method for integrally carbonizing and reinforcing a soft foundation, and has conducted basic research on soil carbonization and reinforcement, and has applied for related patents (for example, a soil carbonization and solidification method, ZL 201210097042.2; a soil carbonization and solidification method and apparatus, ZL 201010604013.1; a treatment system and method for reinforcing a soft foundation by using industrial waste gas heat, ZL 201310122135.0; a treatment system and a carbonization pile-forming method for reinforcing a foundation, ZL 2014102039788; a method for reinforcing a soft foundation by filling a pad layer, ZL 2014102729571). The similar characteristics and beneficial effects of the methods are as follows: active oxide powder (mainly active magnesium oxide) is used as a soil body curing agent, and the carbonization reaction can be completed within dozens of minutes or hours under the environment of high-concentration and high-pressure carbon dioxide, so that the strength of the soil body can be rapidly improved by the generated magnesium compound; compared with cement solidified soil, the cement solidified soil has the characteristics of high solidification speed, high strength, good environmental benefit and the like, and accords with the development trend of green construction of civil engineering. However, according to the methods proposed in the prior patents of "a method and apparatus for carbonizing and solidifying soil (ZL 201010604013.1)" and "a system and method for treating soft soil foundation by using industrial waste gas heat" (ZL 201310122135.0) ", carbon dioxide gas is liable to leak along the stirring shaft, causing secondary pollution; if the perforated air duct is directly inserted into the active magnesium oxide treated pile body, the strength of the pile body is improved, but the material and time are wasted. A treatment system for foundation reinforcement and a carbonization pile-forming method (ZL2014102039788) solve the problem of carbon dioxide gas leakage to a certain extent, but have higher requirements on a carbon dioxide foam foaming agent and the stabilization time thereof, additionally increase the water content and the porosity of foundation soil, have less obvious strength increase, and have poorer reinforcement effect particularly for natural foundations with high water content. A filling and padding layer replacing carbonization strengthening method (ZL2014102729571) for a soft soil foundation adopts mixed materials with different grain diameters for filling and carbonization, ensures the uniformity of foundation treatment and the obvious improvement of foundation strength, but large-area foundation filling and padding increase the engineering quantity and cost of foundation treatment and reduce the construction efficiency. In addition, research shows that the initial water content and the compaction degree of the soil body have great influence on the carbonization effect. However, in the existing carbonization treatment technology, a method for determining relevant parameters of the carbonization process, such as gas pressure, gas injection interval, aeration time and the like, is not given.

Based on the current situation of rapid development of engineering construction in China and the advantages of a novel foundation carbonization and reinforcement method, the carbonization progress monitoring device for magnesia cement solidified soft soil is urgently needed to be developed by combining the defects of the conventional carbonization and reinforcement method, and has important significance in the aspects of effectively utilizing carbon dioxide, saving materials, saving time, realizing efficient construction and the like.

SUMMERY OF THE UTILITY MODEL

The technical problem is as follows:

for overcoming the weak point in the present magnesium oxide carbonization treatment process, the utility model aims at providing a carbonization progress monitoring devices of magnesium oxide cement solidification weak soil that can acquire carbonization technical parameter fast to realize the resourceful reuse of magnesium oxide and carbon dioxide in engineering construction.

The technical scheme is as follows:

in order to achieve the above object, we disclose a device for monitoring the carbonization process of magnesia cement-cured soft soil, which mainly comprises: a carbon dioxide gas tank, a cylindrical barrel, a sensor, an alkali liquor tank and a data acquisition device,

a top cover plate of the cylindrical barrel is provided with a quick joint, and a carbon dioxide gas tank is connected with the quick joint through a vent pipe; a fixed pull rod is arranged on a bottom plate of the cylindrical barrel, and the top cover plate can be pressed on the cylindrical barrel through a bolt and the fixed pull rod cover; a sampling hole and a mounting hole of a sensor are preset on the side wall of the cylindrical barrel; the sensors comprise pore pressure meters, temperature sensors and humidity sensors, and are respectively connected with the data acquisition device through data lines;

an exhaust pipe is arranged on a bottom plate of the cylindrical barrel, a control valve is arranged on the exhaust pipe, an alkali liquor tank is arranged at the lower part of the exhaust pipe, the alkali liquor tank is arranged on an electronic scale, and the electronic scale is arranged on a base frame; the cylindrical barrel is fixedly connected with the base frame;

as an improvement of the utility model, the cylindrical barrel is made of organic glass or stainless steel and can bear 1MPa of air pressure.

As another improvement of the utility model, the pore pressure gauge, the temperature sensor and the humidity sensor are arranged at the same height of the cylindrical barrel, and each sensor is arranged according to the height of the soil column in a layered way, and the height of each layer is 10-20 cm.

Has the advantages that:

compared with the prior art, the utility model discloses the beneficial effect who has is:

(1) the device can monitor the pore pressure, temperature and water content changes of the magnesium oxide solidified soil column at different depths in real time, and analyze the change rule of monitoring data along with the initial air pressure and carbonization time so as to determine the optimal ventilation pressure and carbonization time under different initial water contents and compactedness.

(2) The alkali liquor tank is specially arranged, so that waste gas and waste liquid in the test process can be absorbed, and environmental pollution is avoided.

(3) All sensors are connected with a data acquisition device, the structure is highly uniform, the system continuity is strong, the operation is simple and convenient, the manpower is greatly reduced, the acquired parameters provide guidance for the field carbonization and reinforcement of the soft soil foundation, and the processing efficiency is improved.

Drawings

FIG. 1 is a schematic structural diagram of a carbonization process monitoring device for magnesia cement-cured soft soil;

in the figure: 1. carbon dioxide gas pitcher, 2, gas pressure regulating valve, 3, breather pipe, 4, the joint soon, 5, bolt, 6, lamina tecti, 7, cylinder bucket, 8, porous disk, 9, filter paper, 10, fixed pull rod, 11, solidification soil, 12, thief hole, 13, blast pipe, 14, control valve, 15, lye tank, 16, electronic scale, 17, base frame, 18, pore pressure gauge, 19, temperature sensor, 20, humidity transducer, 21, data acquisition device.

Detailed Description

In order to make the technical means, the creation characteristics, the achievement purposes and the efficacy of the invention easy to understand, the invention is further explained below with the accompanying drawings.

The utility model provides a carbonization process monitoring devices of magnesium oxide cement solidification weak soil, the device mainly includes: a carbon dioxide gas tank 1, a cylindrical barrel 7, a sensor, an alkali liquor tank 15 and a data acquisition device 21,

a top cover plate 6 of the cylindrical barrel 7 is provided with a quick-connection joint 4, and the carbon dioxide gas tank 1 is connected with the quick-connection joint 4 through a vent pipe 3; a fixed pull rod 10 is arranged on a bottom plate of the cylindrical barrel 7, and the top cover plate 6 can be covered on the cylindrical barrel 7 through a bolt 5 and the fixed pull rod 10; a sampling hole 12 and a mounting hole of a sensor are preset on the side wall of the cylindrical barrel 7; the sensors comprise a pore pressure meter 18, a temperature sensor 19 and a humidity sensor 20, and the sensors are respectively connected with a data acquisition device 21 through data lines;

an exhaust pipe 13 is arranged on the bottom plate of the cylindrical barrel 7, a control valve 14 is arranged on the exhaust pipe 13, an alkali liquor tank 15 is arranged at the lower part of the exhaust pipe 13, the alkali liquor tank 15 is arranged on an electronic scale 16, and the electronic scale 16 is arranged on a base frame 17; the cylindrical barrel 7 is fixedly connected with a base frame 17;

as an improvement of the utility model, the cylindrical barrel 7 is made of organic glass or stainless steel and can bear 1MPa of air pressure.

As another improvement of the utility model, the pore pressure gauge 18, the temperature sensor 19 and the humidity sensor 20 are arranged at the same height of the cylindrical barrel 7, and each sensor is arranged according to the height of the earth pillar in layers, and the height of each layer is 10-20 cm.

A carbonization process monitoring device for magnesia cement cured soft soil can be implemented according to the following steps:

a. preparing a magnesium oxide-soft soil mixture: mixing a certain amount of magnesium oxide with natural soft soil by stirring, and testing the water content of the natural soft soil and the mixed soil;

b. preparing a soil column: firstly, sequentially laying a permeable plate 8 and filter paper 9 on the inner bottom of a cylindrical barrel 7, then laying and pressing a magnesium oxide-soft soil mixture into the cylindrical barrel 7 in a layered mode, and finally sequentially laying the filter paper 9 and the permeable plate 8 on a soil column, wherein the compaction degree is determined according to the mass of the mixture and the height of the soil column, the height of the soil column is 70cm, and the initial range of the compaction degree is 82% -96%;

c. aeration carbonization and data monitoring: the distance between the preformed holes of the soil column sensors is 10-20cm, the soil columns where the three sensors are located are consistent in height, the inserting positions of the sensors are sealed and air-tight, the sensors are connected to a data acquisition device 21, a gas pressure regulating valve (2) is opened for ventilation carbonization, the ventilation pressure is 100-800kPa, and the ventilation time is 24 hours;

d. waste liquid/waste gas collection: after carbonization, the control valve 14 is opened, and waste liquid and waste gas generated in the process flow are absorbed through the alkali liquor tank 15;

e. data processing and parameter determination: and analyzing the change rules of pore pressure, temperature and water content under different compaction degrees and carbon dioxide pressure, establishing a correlation relationship, and providing guidance for determining optimal parameters.

Claims (3)

1. The utility model provides a carbonization process monitoring devices of magnesium oxide cement solidification weak soil, the device mainly includes: carbon dioxide gas pitcher, cylinder bucket, sensor, lye tank and data acquisition device, be equipped with the quick-connect joint on the lamina tecti of cylinder bucket, carbon dioxide gas pitcher passes through the breather pipe and connects the joint with the quick-connect, fixed pull rod has been installed on the bottom plate of cylinder bucket, lamina tecti accessible bolt and fixed pull rod lid are pressed on the cylinder bucket, the mounting hole of thief hole and sensor has been preset on the lateral wall of cylinder bucket, the sensor includes pore pressure meter, temperature sensor and humidity transducer, the sensor is connected with data acquisition device through the data line respectively, be equipped with the blast pipe on the bottom plate of cylinder bucket, have the control valve on the blast pipe, there is the lye tank blast pipe lower part, and the lye tank is placed on the electronic scale, and the electronic scale is placed on the base frame, cylinder bucket and base frame fixed connection.

2. A magnesia cement hardened soft soil carbonization progress monitoring device according to claim 1, characterized in that: the cylindrical barrel is made of organic glass or stainless steel and can bear the air pressure of 1 MPa.

3. A magnesia cement hardened soft soil carbonization progress monitoring device according to claim 1, characterized in that: the pore pressure meter, the temperature sensor and the humidity sensor are arranged at the same height of the cylindrical barrel, each sensor is arranged in a layered mode according to the height of the soil column, and the height of each layer is 10-20 cm.

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