Soft soil foundation reinforcing system combining vacuum preloading and positive pressure air bag air outlet rods

Abstract

The invention discloses a soft soil foundation reinforcing system combining vacuum preloading with a positive-pressure air bag air outlet rod. According to the system, the air outlet rod with an air bag and a positive-pressure supply device are combined on the basis of a vacuum preloading foundation drainage system. An air outlet rod with an air bag is arranged at the central position of every four plastic drainage plates which are arranged in a square shape; and the top ports of all the air outlet rods with the air bags are connected with a positive pressure supply device. The positive pressure supply device inputs high-pressure air to the air outlet rods with the air bags through the transverse pipelines, so that the air holes of the air outlet rods with the air bags blow out the high-pressure air outwards in the transverse direction, the high-pressure air moves towards the plastic drainage plates on the periphery, and then the high-pressure air and the negative pressure working state of the vacuum preloading foundation drainage system cooperate to promote drainage. Meanwhile, the air bags on the air outlet rods with the air bags are inflated and expanded to compact surrounding soil under the action of positive pressure, so that ultra-static pore water pressure is generated in the extruded soil, and the drainage and reinforcement effect of the foundation is further improved.

Description

Technical Field

[0001] This invention belongs to the field of soft soil foundation reinforcement technology, and in particular relates to a soft soil foundation reinforcement system with vacuum preloading combined with positive pressure airbag outlet rod. Background Technology

[0002] In recent years, with the continuous and vigorous development of port trade and the improvement of my country's economic status in the international environment, the existing port yards and berths can no longer meet the needs of shipping. As a result, large-scale land reclamation and yard renovation (expansion) projects have emerged. However, the high water level in coastal areas, the poor physical and mechanical properties of the soil, and the wide distribution of soft soil have always been a problem restricting the effectiveness and quality of soft foundation reinforcement. Engineering accidents caused by uneven settlement and large post-construction settlement in existing yards and wharves are common.

[0003] Traditional vacuum preloading for soft soil foundation reinforcement is widely used in coastal and riverside areas of my country. It boasts significant advantages such as short construction period, remarkable reinforcement effect, minimal environmental impact, and high construction safety. However, it also has some drawbacks, such as limited reinforcement depth. The reinforcement depth of vacuum preloading is typically limited by the effective drainage depth of the drainage system. Furthermore, traditional vacuum preloading technology is constrained by factors such as the vacuum level (usually 80-90 kPa) and its transfer efficiency (vacuum attenuation studies typically show a range of 2-7 kPa / m). Generally, its effective reinforcement depth is around 10 meters, which is insufficient for deep soft soil foundations. For soil layers, the reinforcement effect is not ideal, and it is usually necessary to combine it with other reinforcement methods to achieve the reinforcement depth required by the design. The scope of application is somewhat limited. Although the vacuum preloading method is applicable to a variety of soft soil foundations, its reinforcement effect may be affected for some special geological conditions, such as deep soft soil layers and soft soil foundations with extremely high water content. It is necessary to use it in combination with other methods. In addition, with the continuous improvement of soft soil reinforcement technology, the reinforcement mechanism and effect of traditional processes are constantly being updated. Therefore, the traditional vacuum preloading process also needs to be continuously improved and upgraded to meet the needs of key projects for soft soil reinforcement efficiency.

[0004] Therefore, the traditional vacuum preloading soft soil reinforcement process still faces many problems and challenges in its application and development. The research and innovation of new soft soil reinforcement technologies still have a long way to go. To address this, a new soft soil reinforcement method based on vacuum preloading technology is proposed. Summary of the Invention

[0005] The purpose of this invention is to address the shortcomings of existing technologies by providing a soft soil foundation reinforcement system with vacuum preloading combined with positive pressure airbag outlet rod.

[0006] This invention is achieved through the following technical solution: A soft soil foundation reinforcement system combining vacuum preloading and positive pressure airbag outlet rod includes: an outlet rod with an airbag, a positive pressure supply device, and a vacuum preloading foundation drainage system. The structure of the vacuum preloading foundation drainage system is as follows: In the soft soil foundation to be treated, multiple plastic drainage boards are arranged vertically and in a dot matrix. A sand layer is laid on the soft soil foundation, and a sealing membrane is laid on the sand layer. The sealing membrane is sealed around its perimeter. A horizontal drainage collection pipe is buried in the sand layer. The drainage collection pipe leads the sealing membrane upward through the first vertical pipe and the first membrane outlet device and connects to the air extraction and drainage device. The structure of the air-filled rod with an airbag is as follows: it includes a steel pipe body, the bottom of the steel pipe body is a closed pointed structure, multiple air holes are opened on the pipe wall of the steel pipe body, and an airbag is installed on the steel pipe body. The airbag is connected to the inside of the steel pipe body through an air passage. The air-filled vent rod is vertically installed in the soft soil foundation of the vacuum preloading foundation drainage system. The arrangement between the air-filled vent rod and the plastic drainage board in the vacuum preloading foundation drainage system is as follows: an air-filled vent rod is placed at the center of every four plastic drainage boards arranged in a square. The top ports of all the air-filled bladders are connected to the horizontal pipes, which are buried in the sand layer of the vacuum preloading foundation drainage system. The horizontal pipes lead the sealing membrane upward through the second vertical pipe and the second membrane outlet device and connect it to the positive pressure supply device.

[0007] In the above technical solution, the drainage collection pipe is provided with permeable holes, which are wrapped with filter cloth.

[0008] In the above technical solution, the number of airbags on the air outlet rod with airbags is multiple, and they are arranged at intervals along the length of the steel pipe body.

[0009] In the above technical solution, the main body of the air-filled rod with airbag is composed of multiple pipe segments connected by threads.

[0010] In the above technical solution, the main body of the steel pipe of the air outlet rod with airbag includes an air hole section and an airbag section, which are connected by threads. The air hole section has air holes on its pipe wall and a filter cloth is tied to its surface. The airbag section includes a steel pipe base, an elastic airbag skin, and a clamp. Two grooves are provided on the outer wall of the steel pipe base. The upper and lower ends of the airbag skin are respectively wrapped and fixed to the grooves by the clamp to form an airbag cavity. An air passage communicating with the airbag cavity is provided on the steel pipe base. External threads are provided at both ends of the steel pipe base for connecting the air hole section.

[0011] In the above technical solution, the vent pipe section is a steel pipe with a length of 1.0-1.5m and a diameter of 5-10cm.

[0012] In the above technical solution, during operation, the positive pressure supply device inputs high-pressure air into each air-filled vent rod through a horizontal pipeline. This causes the air holes of the air-filled vent rods to blow high-pressure gas outward laterally. This high-pressure gas moves towards the surrounding plastic drainage boards, thus working in conjunction with the negative pressure working state of the vacuum preloading foundation drainage system. This creates numerous microchannels in the soil between the air-filled vent rods and the surrounding plastic drainage boards. Airflow is generated in these microchannels, moving from the air-filled vent rods towards the surrounding plastic drainage boards. This causes water in the soil to move along the microchannels and airflow towards the plastic drainage boards, entering the plastic drainage boards and promoting drainage. Simultaneously, under the positive pressure, the air bladders on the air-filled vent rods inflate and expand, compacting the surrounding soil. This generates excess pore water pressure within the compressed soil, promoting water exudation from the soil and further improving the foundation drainage and reinforcement effect.

[0013] The advantages and beneficial effects of this invention are as follows: This invention combines an air-filled venting rod with an air bladder and a positive pressure supply device with a vacuum preloading foundation drainage system. An air-filled venting rod with an air bladder is placed at the center of every four square-arranged plastic drainage boards. The top ends of all the air-filled venting rods are connected to horizontal pipes, which are buried in the sand layer of the vacuum preloading foundation drainage system. The horizontal pipes extend upwards through vertical pipes and a membrane outlet device to produce a sealing membrane, which is then connected to the positive pressure supply device. During operation, the positive pressure supply device supplies high-pressure air to each air-filled vent rod via a horizontal pipeline. This causes the air holes of the vent rods to blow high-pressure gas outward laterally. This high-pressure gas moves towards the surrounding plastic drainage boards, working in synergy with the negative pressure of the vacuum preloading foundation drainage system. This creates numerous microchannels in the soil between the air-filled vent rods and the surrounding plastic drainage boards. Airflow is generated within these microchannels, moving from the air-filled vent rods towards the surrounding plastic drainage boards. This causes water in the soil to move along the microchannels and airflow towards the plastic drainage boards, entering them and promoting drainage. Simultaneously, under positive pressure, the air bladders on the vent rods inflate and expand, compacting the surrounding soil. This creates excess pore water pressure within the compressed soil, promoting water extraction and further enhancing the foundation drainage and reinforcement effect. Attached Figure Description

[0014] Figure 1 This is a schematic diagram of the soft soil foundation reinforcement system of the vacuum pre-compression combined positive pressure airbag outlet rod of the present invention.

[0015] Figure 2 This is a top view diagram showing the arrangement between the air vent rod with an airbag and the plastic drainage board.

[0016] Figure 3 This is a three-dimensional schematic diagram showing the arrangement of the air vent rod with an airbag and the plastic drainage board.

[0017] Figure 4 This is a schematic diagram of the basic structure of the air delivery rod with an airbag.

[0018] Figure 5 This is a schematic diagram of the segmented connection of the air outlet rod with an airbag.

[0019] For ordinary technicians in this field, other relevant drawings can be obtained based on the above drawings without any creative work. Detailed Implementation

[0020] The present invention will be further described in detail below with reference to the accompanying drawings and specific embodiments. It should be understood that the specific embodiments described herein are merely illustrative of the invention and are not intended to limit the invention.

[0021] See Figure 1 A soft soil foundation reinforcement system combining vacuum preloading and positive pressure airbag outlet rod includes: an outlet rod 1 with an airbag, a positive pressure supply device 2, and a vacuum preloading foundation drainage system.

[0022] The structure of the vacuum preloading foundation drainage system is as follows: In the soft soil foundation to be treated, multiple plastic drainage boards 3 are arranged vertically and in a dot matrix. The top of the plastic drainage boards 3 protrudes a certain length from the surface of the soft soil foundation. A sand layer 4 is laid on the soft soil foundation, and a sealing membrane 6 is laid on the sand layer 4 (preferably, a woven or non-woven fabric can be laid under the sealing membrane 6 as a protection to prevent the sealing membrane 6 from being squeezed and broken by the sand layer). A membrane pressing trench 7 is excavated around the soft soil foundation to be treated to seal the sealing membrane 6, thereby forming a closed environment in the soft soil foundation area to be treated. A horizontal drainage collection pipe 5 is buried in the sand layer 4. The drainage collection pipe 5 has water permeable holes distributed on it (the water permeable holes are wrapped with filter cloth to prevent sand or other impurities from entering the interior of the drainage collection pipe 5), so that the drainage collection pipe 5 is connected to the sand layer 4 and the plastic drainage boards 3. The drainage collection pipe 5 leads the sealing membrane 6 upward through the first vertical pipe and the first membrane outlet device 81 and connects it to the air extraction drainage device 9 (also known as a water vapor separation pump). During operation, the vacuum drainage device 9 generates negative pressure. This negative pressure is transmitted to the soft soil foundation through the drainage collection pipe 5, the sand layer 4, and the plastic drainage board 3. Under the action of negative pressure, water and air in the soft soil foundation enter the plastic drainage board 3 and are collected upwards along the plastic drainage board 3 to the drainage collection pipe 5. Finally, they enter the vacuum drainage device along the drainage collection pipe 5, thereby achieving drainage and reinforcement of the soft soil foundation.

[0023] Based on the aforementioned vacuum preloading foundation drainage system, this invention combines an air outlet rod 1 with an airbag and a positive pressure supply device 2.

[0024] See appendix Figure 4 The structure of the air-filled rod 1 with airbags is as follows: it includes a steel pipe body 101, the bottom of the steel pipe body 101 is a closed pointed structure, which makes it easy to insert into the foundation. Multiple air holes 102 are opened on the pipe wall of the steel pipe body 101, and an airbag 103 is installed on the steel pipe body 101. The airbag 103 is connected to the inside of the steel pipe body 101 through an air passage. There are multiple airbags 103, which are arranged at intervals along the length of the steel pipe body 101.

[0025] For further details, please refer to the appendix. Figure 5 The main body 101 of the steel pipe is composed of multiple pipe segments connected by threads, including a vent pipe segment 111 and an airbag pipe segment 112, which are connected by threads. The vent pipe segment 111 is a steel pipe with a length of 1.0-1.5m and a diameter of 5-10cm, and its pipe wall is provided with vent holes 102 and the surface is bound with filter cloth. The airbag tube section 112 includes a steel pipe base 1121, an elastic airbag skin 1122, and a clamp 1123. The outer wall of the steel pipe base 1121 is provided with two vertically distributed grooves 11211. The upper and lower ends of the airbag skin 1122 are respectively wrapped and fixed to the grooves 11211 by the clamp 1123, thereby forming an airbag cavity. An air passage 1124 communicating with the airbag cavity is provided on the steel pipe base 1121, thereby realizing the inflation of the airbag cavity. In addition, external threads 11212 are provided at both ends of the steel pipe base 1121 for connecting the air hole tube section 111.

[0026] The air outlet rod 1 with an air bladder is vertically installed in the soft soil foundation of the vacuum preloading foundation drainage system. Further details can be found in the appendix. Figure 2 and attached Figure 3 The arrangement between the air-filled vent rod 1 and the plastic drainage board 3 in the vacuum preloaded foundation drainage system is as follows: an air-filled vent rod 1 is placed at the center of every four plastic drainage boards 3 arranged in a square.

[0027] The top ports of all the air-filled vent rods 1 are connected to the horizontal pipe 10, which is buried in the sand layer 4 of the vacuum preloading foundation drainage system. The horizontal pipe 10 leads the sealing membrane 6 upwards through the second vertical pipe and the second membrane outlet device 82, and connects to the positive pressure supply device 2. During operation, the positive pressure supply device 2 inputs high-pressure air into each air-filled vent rod 1 through the horizontal pipe 10, causing the air holes 102 of the air-filled vent rod 1 to blow high-pressure gas outwards laterally (see Appendix). Figure 3(As indicated by the arrows in the image), these high-pressure gases move towards the surrounding plastic drainage boards 3, thus working in synergy with the negative pressure state of the vacuum preloading foundation drainage system. This creates numerous tiny channels in the soil between the air-filled exhaust rod 1 and the surrounding plastic drainage boards 3. Airflow is generated within these channels, moving from the air-filled exhaust rod 1 towards the surrounding plastic drainage boards 3. Water in the soil can then move along these tiny channels and the airflow towards the plastic drainage boards 3, entering them and promoting drainage. Simultaneously, the air bladders on the air-filled exhaust rod 1 inflate and expand under positive pressure, compacting the surrounding soil. This generates excess pore water pressure within the compressed soil, promoting water extraction. Under the combined effects of vacuum preloading and the aforementioned airflow, the extracted water enters the plastic drainage boards 3, further enhancing the foundation drainage and reinforcement effect.

[0028] The construction method of the soft soil foundation reinforcement system with vacuum preloading combined with positive pressure airbag outlet rod described in this invention is as follows: Step 1: Lay a subgrade in the soft soil foundation area to meet the conditions for mechanical operation.

[0029] Step 2: In the soft soil foundation area to be treated, install plastic drainage boards 3 and air vent rods 1 with airbags; the plastic drainage boards 3 are arranged in a dot matrix, and an air vent rod 1 with an airbag is placed at the center of every 4 plastic drainage boards 3 arranged in a square.

[0030] Step 3: Lay a sand layer 4, and lay a horizontal drainage collection pipe 5 and a horizontal pipe 10 in the sand layer 4, and connect the top ports of all the air-filled bladders 1 to the horizontal pipe 10.

[0031] Step 4: A sealing membrane 6 is laid on the sand layer 4 (preferably, a woven or non-woven fabric can also be laid under the sealing membrane 6 as a protection to prevent the sealing membrane 6 from being squeezed and broken by the sand layer), and a pressing trench 7 is dug around the soft soil foundation to be treated to seal the sealing membrane 6, thereby forming a closed environment in the soft soil foundation area to be treated.

[0032] Step 5: Lead the drainage collection pipe 5 upward through the first vertical pipe and the first membrane outlet device 81 to the sealing membrane 6 and connect it to the air extraction and drainage device 9 (also known as a water vapor separation pump); lead the horizontal pipe 10 upward through the second vertical pipe and the second membrane outlet device 82 to the sealing membrane 6 and connect it to the positive pressure supply device 2.

[0033] Step 6: Use the air extraction and drainage device 9 and the positive pressure supply device 2 to drain and reinforce the soft soil foundation.

[0034] Furthermore, preferably, the drainage reinforcement process is carried out according to the following steps: Step 6.1: Activate only the vacuum drainage device 9 to perform traditional vacuum preloading foundation drainage. During this stage, due to the high moisture content in the initial soft soil foundation, rapid and efficient foundation drainage can be achieved.

[0035] Step 6.2: As vacuum preloading foundation drainage proceeds, the soil moisture content gradually decreases, and the drainage rate also gradually decreases, increasing the energy consumption of the vacuum drainage device 9. Therefore, once the drainage rate falls below a certain threshold, step 6.2 is performed. In step 6.2, the vacuum drainage device 9 and the positive pressure supply device 2 are simultaneously activated, working synergistically to drain the foundation, which greatly improves the drainage rate and effectiveness. Specifically, when the two work together, numerous tiny channels are formed in the soil between the air-filled exhaust rod and the surrounding plastic drainage boards. Airflow is generated within these channels, moving from the air-filled exhaust rod towards the surrounding plastic drainage boards. This causes water in the soil to move along the tiny channels and airflow towards the plastic drainage boards, entering them and promoting drainage. Simultaneously, the air bladders on the exhaust rod inflate under positive pressure, compacting the surrounding soil and creating excess pore water pressure within the compressed soil. This promotes water extraction from the soil, further enhancing the foundation drainage and reinforcement effect. Furthermore, during the combined operation of the air extraction and drainage device 9 and the positive pressure supply device 2, the negative pressure provided by the air extraction and drainage device 9 is greater than the positive pressure provided by the positive pressure supply device 2. This ensures that the entire foundation remains under negative pressure during their combined operation.

[0036] Step 6.3: Since the air extraction and drainage device 9 and the positive pressure supply device 2 are turned on at the same time in step 6.2, many tiny channels can be formed in the foundation. However, due to the input of positive pressure gas in the foundation, the negative pressure in the foundation will be reduced. Therefore, if step 6.2 is carried out for a long time, the drainage effect is not optimal.

[0037] Therefore, after running for a period of time in step 6.2, the positive pressure supply device 2 should be stopped, and step 6.3 should be performed. In step 6.3, only the vacuum drainage device 9 is turned on to perform the traditional vacuum pre-pressure drainage work again. At this time, since many tiny channels have been formed in the foundation in step 6.2, turning on only the vacuum drainage device 9 in step 6.3 can both utilize the formation of tiny channels and greatly increase the negative pressure in the foundation, thereby improving the drainage effect.

[0038] Step 6.4: Repeat steps 6.2 and 6.3 alternately multiple times.

[0039] Step 6.5: Stop the positive pressure supply device 2 and only start the air extraction and drainage device 9 to perform foundation drainage and reinforcement. This step is to finally extract water and gas from the foundation. This is because when the positive pressure supply device 2 is working, it increases the gas content in the foundation. Therefore, in the final stage, the positive pressure supply device 2 must be stopped, and only the air extraction and drainage device 9 must be started.

[0040] For ease of explanation, spatial relative terms such as “up,” “down,” “left,” and “right” are used in the embodiments to describe the relationship of one element or feature shown in the figures relative to another element or feature. It should be understood that, in addition to the orientations shown in the figures, spatial terms are intended to include different orientations of the device in use or operation. For example, if the device in the figures is inverted, an element described as being “down” of other elements or features would be positioned “up” of those other elements or features. Therefore, the exemplary term “down” can encompass both up and down orientations. The device may be positioned in other ways (rotated 90 degrees or in other orientations), and the spatial relative descriptions used herein will be interpreted accordingly.

[0041] Moreover, relational terms such as “first” and “second” are used merely to distinguish one component from another that has the same name, without necessarily requiring or implying any such actual relationship or order between the components.

[0042] The above description is only a preferred embodiment of the present invention. It should be noted that, for those skilled in the art, several improvements and modifications can be made without departing from the principle of the present invention, and these improvements and modifications should also be considered within the scope of protection of the present invention.

Claims

1. A soft soil foundation reinforcement system using vacuum preloading combined with a positive pressure airbag outlet rod, characterized in that, include: An air-filled exhaust mandrel, a positive pressure supply device, and a vacuum preloading foundation drainage system; The structure of the vacuum preloading foundation drainage system is as follows: In the soft soil foundation to be treated, multiple plastic drainage boards are arranged vertically and in a dot matrix. A sand layer is laid on the soft soil foundation, and a sealing membrane is laid on the sand layer. The sealing membrane is sealed around its perimeter. A horizontal drainage collection pipe is buried in the sand layer. The drainage collection pipe leads the sealing membrane upward through the first vertical pipe and the first membrane outlet device and connects to the air extraction and drainage device. The structure of the air-filled rod with an airbag is as follows: it includes a steel pipe body, the bottom of the steel pipe body is a closed pointed structure, multiple air holes are opened on the pipe wall of the steel pipe body, and an airbag is installed on the steel pipe body. The airbag is connected to the inside of the steel pipe body through an air passage. The air-filled vent rod is vertically installed in the soft soil foundation of the vacuum preloading foundation drainage system. The arrangement between the air-filled vent rod and the plastic drainage board in the vacuum preloading foundation drainage system is as follows: an air-filled vent rod is placed at the center of every four plastic drainage boards arranged in a square. The top ports of all the air-filled bladders are connected to the horizontal pipes, which are buried in the sand layer of the vacuum preloading foundation drainage system. The horizontal pipes lead the sealing membrane upward through the second vertical pipe and the second membrane outlet device and connect it to the positive pressure supply device.

2. The soft soil foundation reinforcement system with vacuum preloading combined with positive pressure airbag outlet rod according to claim 1, characterized in that, The drainage collection pipe has permeable holes, which are wrapped with filter cloth.

3. The soft soil foundation reinforcement system with vacuum preloading combined with positive pressure airbag outlet rod according to claim 1, characterized in that, The number of airbags on the air outlet rod with airbags is multiple, and they are arranged at intervals along the length of the steel pipe body.

4. The soft soil foundation reinforcement system with vacuum preloading combined with positive pressure airbag outlet rod according to claim 1, characterized in that, The main body of the air-filled rod with airbag is composed of multiple pipe sections connected by threads.

5. The soft soil foundation reinforcement system with vacuum preloading combined with positive pressure airbag outlet rod according to claim 1, characterized in that, The main body of the air-filled rod with an air bladder includes an air hole section and an air bladder section, which are connected by threads. The air hole section has air holes on its wall and a filter cloth is wrapped around its surface. The air bladder section includes a steel pipe base, an elastic air bladder skin, and a clamp. The outer wall of the steel pipe base has two grooves distributed vertically. The upper and lower ends of the air bladder skin are respectively wrapped and fixed to the grooves by the clamp to form an air bladder cavity. An air passage communicating with the air bladder cavity is provided on the steel pipe base. External threads are provided at both ends of the steel pipe base for connecting the air hole section.

6. The soft soil foundation reinforcement system with vacuum preloading combined with positive pressure airbag outlet rod according to claim 1, characterized in that, The vent pipe section is made of steel pipe with a length of 1.0-1.5m and a diameter of 5-10cm.

7. The soft soil foundation reinforcement system with vacuum preloading combined with positive pressure airbag outlet rod according to claim 1, characterized in that, The positive pressure supply device supplies high-pressure air to each air-filled bladder-equipped air outlet rod through a horizontal pipeline. This causes the air outlet rod to blow high-pressure gas outward laterally. The high-pressure gas moves towards the surrounding plastic drainage boards, thus working in conjunction with the negative pressure operation of the vacuum preloading foundation drainage system. This creates numerous microchannels in the soil between the air outlet rod and the surrounding plastic drainage boards. Airflow is generated within these microchannels, moving from the air outlet rod towards the surrounding plastic drainage boards. This causes water in the soil to move along the microchannels and airflow towards the plastic drainage boards, entering them and promoting drainage. Simultaneously, under the positive pressure, the air bladders on the air outlet rods inflate and expand, compacting the surrounding soil. This generates excess pore water pressure within the compressed soil, promoting water expulsion and further enhancing the foundation drainage and reinforcement effect.

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