Patent Application
20220341116
The present invention relates to a method for foundation consolidation combining vacuum preloading and geomembrane bag assembly loading.
With rapid economic and social development as well as soaring population in coastal areas, the demand for land resources is becoming increasingly compelling. Therefore, tideland reclamation is becoming an important means of land resource development for many countries in the world. Generally, mud can be categorized into dredged mud, reclaimed silt and construction waste mud. These kinds of mud feature high water content, high compressibility, and low strength, and the soil mass is in the state of fluid and slurry. However, the conventional vacuum preloading method for foundation consolidation is of poor performance, and cannot meet the requirements for foundation strength and deformation in construction projects, and may often lead to engineering accidents.
Considering the engineering complexity and uneven settlement resulting from conventional vacuum preloading using slag loading, the present invention adopts geomembrane bags for loading to overcome the adverse effects of slag loading. At present, one kind of geomembrane bag treatment method is used quite widely, and can be directly used for loading above the slurry pit dug out in a construction project. Geomembrane bag is a kind of huge membrane bag and inclusion made of high-strength geotextile with its diameter changeable as needed. Geomembrane bags were initially used in embankment engineering, and then gradually applied in environment protection and agricultural fields. Currently, they are also applied in some sludge treatment projects. However, ordinary geomembrane bags have inherent defects in treating pipe mud and dredged mud: firstly, drainage is realized only through the natural settlement of mud and geomembrane bag stacking, and a long period of one to two months is required. The low speed and insufficient dehydration will obviously affect the duration of construction, and consequently lead to increased time cost and economic cost. Therefore, it is not suitable for urgent and complicated foundation consolidation projects; in addition, during the dehydration process through stacking and gravity-based squeezing of the geomembrane bags, the discharged water is very muddy and not immediately recyclable, and requires centralized treatment.
Furthermore, during the foundation consolidation process, the conventional vacuum preloading method has considerable loss of vacuity and low transmission efficiency along the depth, leading to poor treatment of in-depth soil mass and low bearing capacity of the foundation. From a microscopic view, because of the fine soil particles in the mud and the fluid state, during vacuum preloading, the soil particles are discharged along with the pore-water and are displaced. They gradually deposit around the drainage body to form a dense soil column, causing clogging and lower transverse permeability coefficient of the soil mass, and poor drainage and consolidation of the soil mass between drainage bodies; in addition, during the vacuum preloading pump drainage and consolidation process, the fine particles move along with the pore-water and enter the drain board filtering membrane, causing reduced permeability of the filtering membrane. The vacuum pumping generates a lateral pressing force upon the plastic drain board, forcing the filtering membrane into the drainage channel. Due to clogging of the filtering membrane, the vertical drainage flux of the drain board is reduced; the phenomena described above are collectively referred to as vacuum preloading clogging effect. Therefore, in view of the shortcoming of the conventional vacuum preloading, more researches need to be carried out to improve the current vacuum preloading method, and to improve the consolidation efficiency of vacuum preloading.
The object of the present invention is to provide a foundation consolidation method that uses the mud to be treated for loading (the material can be easily obtained), and adopts the technology of vacuum preloading for foundation consolidation, for better transmission of vacuity in the soft soil, higher drainage speed, and higher degree of consolidation.
A further step, said method comprising: a method for foundation consolidation combining vacuum preloading and geomembrane bag assembly loading, which comprises: digging a slurry pit, filling mud into the slurry pit and conducting vacuum preloading pump drainage for several times, place the geomembrane bag assemblies filled with mud above the soft slurry seam drained through vacuum preloading in the slurry pit to form a loading layer, the geomembrane bag assemblies are laid by stacking geomembrane bags.
More particularly, which comprises the following steps:
(1) prefabricate drainage systems and geomembrane bag assemblies for soft slurry seam vacuum preloading pump drainage;
(2) based on vacuum preloading method, fill multiple layers of mud on the soft slurry seam of the slurry pit, and place drainage systems layer by layer. After placement of the drainage systems on every layer, connect them to the vacuum pump assemblies, and start vacuum pumping;
(3) fill and stack the geomembrane bag assemblies;
(4) place second vertical drain boards around the slurry pit, place third transverse drain boards above the upper surface of the geomembrane bag assemblies, and connect the second vertical drain boards and third transverse drain boards to the vacuum pump assemblies for pump drainage.
More particularly, wherein a plurality of vertically arranged second horizontal drainage systems is placed into the soft slurry seam, the second horizontal drainage system includes a plurality of transversely arranged second transverse drain board, both sides of the second horizontal drainage system are respectively and conductively connected via elbows to the corresponding vertical drainpipes on both sides.
More particularly, wherein a plurality of vertical drainage systems is placed into the soft slurry seam; the vertical drainage system includes a plurality of first vertical drain boards, both sides of the first vertical drain board are respectively and conductively connected via elbows to the corresponding vertical drainpipes on both sides.
More particularly, wherein a vertical and horizontal integrated drainage system is placed into the soft slurry seam; the vertical and horizontal integrated drainage system is a drainage system made of multiple rows of second transverse drain boards and multiple columns of first vertical drain boards, both sides of the second transverse drain board are connected with the adjacent first vertical drain boards, the first vertical drain boards are joined and connected to a transverse drainpipe.
More particularly, wherein the second horizontal drainage systems are covered by a geotextile layer, and are laid by the following means:
filling mud into the slurry pit, when the mud filled reaches the preset height, transversely place the firstly layer of second, horizontal drainage systems, and continue filling mud until it covers the geotextile layer of the second horizontal drainage systems, conductively connect the second junction blocks on both sides of the horizontal drainage systems of the first layer via elbows to the vertical drainpipes and start vacuum pumping immediately; repeat the above steps; as vacuum pumping goes on, the mud will sink simultaneously, when the covering mud reaches the standard height required by the construction project, lay the last layer of second horizontal drainage systems, and seal them using a second sealing membrane, so that the soft slurry seam of the slurry pit forms an integral body, and then conduct vacuum pumping.
More particularly, wherein the vertical drainage systems are covered using a geotextile layer, and are laid by the following means:
filling mud into the slurry pit, when the mud filled reaches the preset height, place the vertical drainage system at regular intervals, continue filling in mud until the mud completely covers the vertical drainage systems and reaches the standard height required by the construction project, and then stop filling; connect the vertical drainage systems to the vertical drainpipes in a conductive form, place a layer of second sealing membrane on the surface of the soft slurry seam, and start vacuum pumping.
More particularly, wherein the vertical and horizontal integrated drainage systems are laid by the following means:
filling mud into the soft slurry seam of the slurry pit, when the mud filled reaches the preset height, lay the vertical drainage systems at regular intervals, every time the mud filled reaches the preset height, place a layer of second transverse drain boards between every two vertical drainage systems, the second transverse drain boards are placed in the same direction as the vertical drainage systems; after placing every layer of second transverse drain boards, connect one end of the second transverse drain boards to the vertical drainpipes in a conductive form; repeat the above steps until the mud is filled to the standard height required by the construction project; place a layer of second sealing membrane on the soft slurry seam, finally, start the vacuum pump assemblies for vacuum preloading pump drainage, the vertical drainage systems and second transverse drain boards include the geotextile layer.
More particularly, wherein the geomembrane bag assemblies include sealing geomembrane bags and single geomembrane bags, first horizontal drainage systems are placed inside the sealing geomembrane bags, the first horizontal drainage systems are connected via the pipe system to the vacuum pump assemblies, wherein, sealing geomembrane bags are only laid on the topmost layer of the geomembrane bag assemblies.
More particularly, wherein, the inner wall and outer wail of the sealing geomembrane bags are configured with a first sealing membrane, the first horizontal drainage system includes first transverse drain boards and transverse geotextile to fix the first transverse drain boards, the transverse geotextile is transversely placed in the middle of the sealing geomembrane bag and divides the bag into an upper chamber and lower chamber; the first transverse drain boards are evenly fixed on the transverse geotextile at regular intervals; both ends of each first transverse drain board are connected via hand-type connectors to the pipe system, the first horizontal drainage systems are connected via geogrids to the two ends of the sealing geomembrane bags, the sealing geomembrane bag has a flange for the drainpipe to pass through, at least one end of the first transverse drain board is connected via the pipe system to the vacuum pump assemblies.
The benefits of the present invention are:
(1) By adopting a second horizontal drainage system, the vertical drainage system, and the layout of horizontal and vertical integrated drainage systems and the geomembrane bag assemblies in upper and lower layers, the respective properties of the two drainage systems are fully exploited, resulting in better vacuity transmission effect in the whole soil mass, quicker drainage speed, and higher degree of consolidation, so as to save time cost and economic cost.
(2) By using an integral second horizontal drainage system, an integral vertical drainage system or a horizontal and vertical integrated drainage system, the drain boards in every layer and every column can be maintained in the same plane, the overall structure is stable, and adverse effects resulting from bending or breakage of the drain boards can be avoided. Moreover, the layout is simplified, saving a lot of labor and cost.
(3) The drain board covered by the geotextile layer can have longer useful life, and can effectively reduce soil particles entering the drain board to cause clogging and reduced drainage speed.
(4) The second transverse drain boards and the first vertical drain boards are laid out in an intersecting manner to form a grid structure, thus improving the consolidation effect of the soil mass.
(5) The sealing geomembrane bag provided by the present invention is air-tight and fluid-tight, and is placed with the first horizontal drainage system. Such an arrangement can produce inside the sealing geomembrane bag a structure similar to vacuum preloading reclamation. During drainage of the first transverse drain board, a pressure difference is formed between the inside and outside of the sealing geomembrane bag, and the atmospheric pressure can press the sealing geomembrane bag to accelerate the drainage of the second transverse drain board, thus greatly saving time cost and economic cost. As the surface of the slurry pit is laid with a layer of sealing geomembrane bag assembly, the problem of low drainage efficiency with absence of external pressure can be effectively solved.
(6) The volume of the geomembrane bag can be adjusted as needed. It can have a wide application range, good engineering flexibility, and can be fabricated according to the size of the slurry pit; multiple layers of geomembrane bag assemblies can be continuously manufactured in factories to effectively save production cost; the geomembrane bag assemblies feature low investment, low human resource intensity, and easy and convenient operation.
(7) While using geomembrane bag assemblies to consolidate the sludge, the solid waste material can be used as filling materials to solve the problem of insufficient ground elevation, saving the transportation and material cost of additional filling materials like sand and stone.
Detailed descriptions of the present invention are provided below with reference to the accompanying figures.
Referring to
In the above descriptions, referring to
In the above descriptions, referring to
In the above descriptions, drainage systems 3 is provided inside the soft slurry seam 101. In Embodiment 1, referring to
Referring to
Referring to
In the above descriptions of Embodiments 1, 2, and 3, all of the first vertical drain board 4, the second vertical drain board 10, the first transverse drain board 901, the second transverse drain board 19, and the third transverse drain board 13 include the geotextile layer 15 laid outside. Said first vertical drain board 4, second vertical drain board 10, first transverse drain board 901, second transverse drain board 19, third transverse drain board 13 are completely covered by the geotextile layer 15. The drainpipe can go through the geotextile layer 15. The drain boards covered by geotextile can have longer service life, and can effectively reduce particles entering the first vertical drain board 4, second vertical drain board 10, first transverse drain board 901, second transverse drain board 19, and third transverse drain board 13, causing reduced drainage speed. By adopting integral drainage systems 3, the second transverse drain boards 19 or first vertical drain boards 4 in every layer or every column can be always maintained in the same plane, and the whole structure is stable, thus avoiding adverse effects caused by bending or breakage. The simplified form of deployment can greatly reduce manpower and material resources.
Referring to
Referring to
Part of the mud 22 in the soft slurry seam 101 beneath the slurry pit 1 will leak out during the pumping and consolidation, and the water naturally discharged from the single geomembrane bags 8 will be sucked and discharged through the second vertical drain boards 10 and the third transverse drain boards 13, so as to prevent leaking out from the periphery of the drainage systems 3 laid beneath to affect the drainage. The combination of single geomembrane bags 8, sealing geomembrane bags 9, drainage systems 3, third transverse drain boards 13 and second vertical drain boards 10 can greatly improve the drainage and consolidation effects.
In the above embodiment, the method for foundation consolidation combining vacuum preloading and loading according to the present invention includes:
Prefabricate second horizontal drainage systems 302, and arrange a plurality of second transverse drain boards 19 at regular intervals and fix them. The distance between adjacent second transverse drain boards 19 is 80 cm. Both ends of the second transverse drain board 19 are connected with hand-type connectors 12. The hand-type connectors 12 on the two sides are respectively conductively connected with the first junction blocks 21 on the two sides of the second transverse drain board 19. The first junction blocks 21 on the two sides are both connected with second junction blocks 5. The upper layer and lower layer of the arranged and fixed second transverse drain boards 19 are both laid with geotextile layers 15. The four sides of the upper and lower geotextile layers 15 are sealed and connected. One end of the second junction block 5 is placed inside the geotextile layer 15 and conductively connected with the first junction block 21, while the other side of the second junction block 5 extends out of the geotextile layer 15; and/or
Prefabricated the vertical drainage systems 3, and arrange a plurality of first vertical drain boards 4 at regular intervals and fix them. The distance between the adjacent first vertical drain boards 4 is 80 cm. The two ends of the first vertical drain board 4 are connected with hand-type connectors 12. The hand-type connectors 12 on the two sides are respectively and sequentially and conductively connected with the first junction blocks 21 on the two sides of the first vertical drain board 4. The first junction blocks 21 on the two sides are both conductively connected with second junction blocks 5. The upper and lower layers of the arranged and fixed first vertical drain boards 4 are both laid with geotextile layers 15. The four sides of the upper and lower geotextile layers 15 are sealed and connected. One end of the second junction block 5 is placed inside the geotextile layer 15 and is conductively connected with the first junction block 21, while the other end of the second junction block 5 extends out of the geotextile layer 15;
When prefabricating the drainage system 3, a geogrid 20 can be used to fix the first horizontal drainage system 18 in the middle position of the sealing geomembrane bag 9. Install the flange 14 on the upper surface of the sealing geomembrane bag 9, and conduct processing and sealing according to required specifications to form a completely sealed integral body. Thus the fabrication of the sealing geomembrane bag 9 is completed;
Filling mud 22 into the slurry pit 1, when the height of the mud 22 filled reaches 40 cm, transversely lay the first layer of second horizontal drainage systems 302, then continue filling in mud 22; when the mud 22 covers the geotextile layer 15 of second horizontal drainage systems 302 of the first layer, connect the second junction blocks 5 on both sides of the first layer of second horizontal drainage system 302 with the vertical drainpipe 16 via the elbows 6, and immediately conduct pumping. Meanwhile, continue filling mud 22 into the slurry pit 1; when the height of the second layer of mud 22 reaches 40 cm, lay the second layer of second horizontal drainage systems 302; when the mud 22 covers the geotextile layer 15 of the second layer of second horizontal drainage systems 302, connect the second junction blocks 5 on both sides of the second layer of second horizontal drainage system 302 to the vertical drainpipe 16 via the elbow 6, and immediately conduct pumping; continue filling mud 22 into the slurry pit 1; repeat the above process; as vacuum pumping goes on, the mud 22 will descend simultaneously, until the mud 22 coverage reaches the standard height required by the construction project; then lay the last layer of second horizontal drainage systems 302, and cover the topmost layer of second sealing membrane 7 and seal it, so that the lower layer of the slurry pit 1 forms an integral body, and then conduct vacuum pumping again; vacuum pumping for the second horizontal drainage systems 302 laid in the lower layer is conducted at the initial stage of filling, thus drainage and consolidation of the lower-layer mud 22 are started as soon as possible, and the degree of consolidation of the whole slurry pit 1 is effectively enhanced; or
Filling mud 22 into the slurry pit 1, when the height of the mud 22 filled reaches 40 cm, lay the vertical drainage systems 301 at regular intervals; then, continue filling in mud 22 until the mud 22 completely covers the vertical drainage systems 301 and reaches the standard height required by the construction project, and stop filling; connect the second junction block 5 inside the vertical drainage system 301 with the elbow 6; the elbow 6 is connected with the transverse drainpipe 11, the transverse drainpipe 11 is conductively connected with the vertical drainpipe 16, and the vertical drainpipes 16 are connected to the vacuum pump assemblies 2; place a layer of second sealing membrane 7 on the surface of the soft slurry seam 101, and start vacuum pumping; or
filling mud 22 into the slurry pit 1, when the height of the mud 22 filled reaches 40 cm, lay the vertical drainage systems 301 at regular intervals; every time the height of the mud 22 filled reaches 40 cm, place a layer of second transverse drain boards 19 between each two layers of vertical drainage systems 301; the second transverse drain boards 19 are placed in the same direction as the vertical drainage systems 301; every time a layer of second transverse drain board 19 is placed, one end of the second transverse drain boards 19 is connected to the elbows 6; the elbows 6 are joined via a second junction block 5, which is connected to the third junction block 17; repeat the above steps until the mud 22 is filled to the standard height required by the construction project; place a layer of sealing membrane on the soft slurry seam 101, and start the vacuum pump assemblies 2 for vacuum preloading pump drainage;
(3) Layout of the loading
Filling and pile the single geomembrane bags 8, and place a layer of sealing geomembrane bag 9 on the topmost layer of the stack, then connect the vacuum pump assemblies 2 for drainage;
(4) Place second vertical drain boards 10 and third transverse drain boards 13 around the slurry pit 1, and conduct pumping and drainage to discharge the marginal water with poor treatment effect in the bottom layer and the water discharged from the upper layer of geomembrane bags in the slurry pit 1. Thus the whole drainage process can be conducted steadily.
| Number | Date | Country | Kind |
|---|---|---|---|
| 202110436398.3 | Apr 2021 | CN | national |
