CN114457782A - Anti-liquefaction composite drainage structure suitable for high-fine-grain-content sand layer and construction method of anti-liquefaction composite drainage structure - Google Patents
Anti-liquefaction composite drainage structure suitable for high-fine-grain-content sand layer and construction method of anti-liquefaction composite drainage structure Download PDFInfo
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- CN114457782A CN114457782A CN202210180100.1A CN202210180100A CN114457782A CN 114457782 A CN114457782 A CN 114457782A CN 202210180100 A CN202210180100 A CN 202210180100A CN 114457782 A CN114457782 A CN 114457782A
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- E—FIXED CONSTRUCTIONS
- E02—HYDRAULIC ENGINEERING; FOUNDATIONS; SOIL SHIFTING
- E02D—FOUNDATIONS; EXCAVATIONS; EMBANKMENTS; UNDERGROUND OR UNDERWATER STRUCTURES
- E02D3/00—Improving or preserving soil or rock, e.g. preserving permafrost soil
- E02D3/02—Improving by compacting
- E02D3/10—Improving by compacting by watering, draining, de-aerating or blasting, e.g. by installing sand or wick drains
- E02D3/106—Improving by compacting by watering, draining, de-aerating or blasting, e.g. by installing sand or wick drains by forming sand drains containing only loose aggregates
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- C—CHEMISTRY; METALLURGY
- C02—TREATMENT OF WATER, WASTE WATER, SEWAGE, OR SLUDGE
- C02F—TREATMENT OF WATER, WASTE WATER, SEWAGE, OR SLUDGE
- C02F1/00—Treatment of water, waste water, or sewage
- C02F1/001—Processes for the treatment of water whereby the filtration technique is of importance
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- E—FIXED CONSTRUCTIONS
- E02—HYDRAULIC ENGINEERING; FOUNDATIONS; SOIL SHIFTING
- E02D—FOUNDATIONS; EXCAVATIONS; EMBANKMENTS; UNDERGROUND OR UNDERWATER STRUCTURES
- E02D3/00—Improving or preserving soil or rock, e.g. preserving permafrost soil
- E02D3/02—Improving by compacting
- E02D3/08—Improving by compacting by inserting stones or lost bodies, e.g. compaction piles
Abstract
The invention provides an anti-liquefaction composite drainage structure suitable for a high-fine-grain-content sand layer and a construction method thereof, wherein the anti-liquefaction composite drainage structure suitable for the high-fine-grain-content sand layer comprises a plurality of gravel piles arranged in a foundation to be treated and a gravel cushion layer arranged on the surface of the foundation to be treated, a geotechnical drainage assembly is arranged in each gravel pile, the top end of each geotechnical drainage assembly is inserted into each gravel cushion layer, each geotechnical drainage assembly comprises a drainage pipe and geotechnical cloth wrapped on the outer side wall of the drainage pipe, and drainage holes are formed in the drainage pipe. The invention has low cost and good durability, and the drainage capability is not influenced by the silting of sand layer particles.
Description
Technical Field
The invention belongs to the technical field of foundation treatment, and particularly relates to an anti-liquefaction composite drainage structure suitable for a sand layer with high fine grain content and a construction method thereof.
Background
The traditional sandy soil liquefaction-resistant foundation treatment is generally carried out by adopting a dynamic compaction method, such as a dynamic compaction or vibroflotation compaction method. However, the dynamic compaction method has certain applicability when reinforcing a sand layer with high fine grain content, such as the vibroflotation compaction method is only applicable to sandy soil foundation with fine grain content (the grain diameter is less than 0.075mm) not more than 15%; the dynamic compaction foundation treatment is suitable for sandy soil foundations with a high fine grain content range (30-40%), but the reinforcement depth is generally not more than 10 m. Therefore, for the easily liquefied sand layer with high fine grain content, a drainage-based anti-liquefaction foundation construction method is often needed, and the ultra-pore water pressure generated under the action of an earthquake is quickly dissipated by providing vertical and horizontal drainage channels. In practical engineering application, a common vertical drainage channel mainly comprises a gravel pile, the durability of the gravel pile is good, but the cost is high, and in the pile forming and long-term service process, sand particles in a stratum siltation is generated under the water level change, so that the drainage capacity of the gravel pile is reduced. At present, for a sand layer with high fine grain content, a gravel pile drainage channel is mainly adopted, but the cost of gravel materials is high, and the drainage performance is greatly reduced in the long-term use process; if the drain pipe is used as a drain channel, the cost is low, the hollow drain pipe can ensure that a constant drain section is maintained in the long-term use process, but the drain pipe material has short service life and has the problem of durability.
Disclosure of Invention
The invention aims to provide a liquefaction-resistant composite drainage structure suitable for a sand layer with high fine grain content and a construction method thereof, which have low cost and good durability, and the drainage capability is not influenced by clogging of sand layer particles.
The invention is realized by the following technical scheme:
the utility model provides a be suitable for anti liquefied composite drainage structure of high particulate content sand bed, includes to lay a plurality of rubble piles in the foundation that need handle and to lay the rubble bed course on need handle foundation surface in, is equipped with geotechnological drainage component in the rubble pile, and the top of geotechnological drainage component inserts in the rubble bed course, and geotechnological drainage component includes drain pipe and the geotechnological cloth of parcel on the drain pipe lateral wall, has seted up drainage hole on the drain pipe.
Furtherly, geotechnological drainage subassembly still includes bracing piece, connecting plate and the anchor end that is the back taper shape, and anchor end top opening and inside cavity, bracing piece one end set up bottom in the anchor end, and the other end sets up on the connecting plate, and the bottom setting of drain pipe is served and is connected with the connecting plate in the anchor.
Furthermore, the aperture ratio of the drain pipe is 20-25%, and the inner diameter of the drain pipe is 100-120 mm.
Furthermore, the geotextile is woven by adopting synthetic fibers, and the water permeability coefficient of the geotextile is 10-1cm/s～10- 2cm/s。
Further, the gravel piles are arranged in a square or regular triangle.
The invention also provides a construction method of the composite drainage structure suitable for the anti-liquefaction of the high-fine-grain-content sand layer, which comprises the steps of constructing by adopting a double-layer pipe vibrating pipe, wherein the double-layer pipe vibrating pipe comprises a first outer sleeve, a first inner sleeve and a top plate, the top end of the first outer sleeve is arranged on the top plate, the upper part of the outer side wall of the first outer sleeve is provided with a feed inlet, the first inner sleeve is arranged in the first outer sleeve, the top end of the first inner sleeve is arranged on the top plate, a material conveying channel is formed between the first inner sleeve and the first outer sleeve, the lower part of the material conveying channel is provided with a first valve for opening and closing the material conveying channel, the bottom end of the first inner sleeve is provided with a second valve for opening and closing the bottom end opening of the first inner sleeve, and the top plate is provided with an opening communicated with the inside of the first inner sleeve;
the construction method comprises the following steps:
s1, determining construction hole positions;
s2, constructing gravel piles and geotechnical drainage assemblies at each construction hole site;
s21, fixing the double-layer tube vibrating tube by using a guide frame, so that the double-layer tube vibrating tube is aligned to a construction hole position;
s22, sinking the double-layer tube vibrating tube to a preset design depth through vibration excitation equipment under the condition that the first valve and the second valve are closed;
s23, opening the first valve and the second valve, stopping exciting the vibration equipment, and putting the geotechnical drainage assembly into the first inner sleeve so that the geotechnical drainage assembly slides to a preset design depth along the first inner sleeve;
s24, penetrating broken stones from a feeding hole in the first outer sleeve until the broken stones reach a set filling height in the conveying channel;
s25, pulling the double-layer tube vibrating tube to the ground while vibrating through vibration excitation equipment, and continuously injecting gravel from a feed inlet on the first outer sleeve in the process of pulling the double-layer tube vibrating tube to form a gravel pile;
and S3, paving a gravel cushion.
Further, the double-layer tube sleeve pipe still includes the injection conical head, and the injection conical head includes the sleeve pipe in the second and sets up a plurality of blades on the sleeve pipe lateral wall in the second along the sleeve pipe circumference interval in the second, and sleeve pipe and the coaxial setting of sleeve pipe in the second, the size of sleeve pipe cross section in the second is the same with the size of sleeve pipe cross section in the first, and the setting of second valve is in the sheathed tube bottom in the second, and a plurality of blades set up the bottom at first outer tube.
Further, first valve includes two bolts and two semi-ring shaped movable plates, and two bolt symmetries set up on first interior sleeve pipe, and two semi-ring shaped movable plates are located first interior sleeve pipe both sides, and rotate through the hinge respectively in the both ends of each semi-ring shaped movable plate and connect on two bolts, and/or, the second valve includes the baffle, and the baffle passes through the hinge rotation to be connected in first interior sheathed tube bottom.
Further, in the step of sinking the double-layer pipe vibrating tube to a predetermined design depth by the vibration excitation device, the double-layer pipe vibrating tube is sunk 0.5m and left to vibrate for 30 s.
Further, before the step of pulling up the double-layer pipe vibrating tube to the ground while vibrating through the vibration excitation equipment, the method further comprises the following steps:
driving the double-layer tube vibrating tube to vibrate for 1 minute by using vibration excitation equipment;
in the step of pulling up the double-layer tube vibrating tube to the ground while vibrating by the vibration excitation equipment, the double-layer tube vibrating tube is kept vibrating for 10-20 seconds every time the double-layer tube vibrating tube is lifted by 0.5-1 m.
Compared with the prior art, the invention has the beneficial effects that:
(1) the geotechnical drainage assembly is used as a main drainage channel, constant vertical drainage clearance can be provided, and the phenomenon that the drainage performance of peripheral gravel piles is remarkably reduced due to siltation and the requirement for ultra-pore water pressure dissipation under the action of an earthquake cannot be met is avoided;
(2) the gravel piles at the periphery of the geotechnical drainage assembly can be used as a reverse filter layer of the geotechnical drainage assembly, so that fine particles in an easily liquefied sand bed foundation are prevented from silting up the outer layer of the geotechnical drainage assembly under the action of water flow;
(3) compared with the crushed stone material with the same volume, the geotechnical drainage component has low cost, and compared with the method of simply using the crushed stone pile as a drainage channel, the geotechnical drainage component can obviously reduce the manufacturing cost of anti-liquefaction foundation treatment under the condition of the same replacement rate;
(4) the drainage anti-liquefaction system composed of the gravel pile, the geotechnical drainage assembly and the surface gravel cushion layer can quickly dissipate pore pressure under the action of an earthquake, and plays a role in drainage anti-liquefaction.
Drawings
FIG. 1 is a schematic structural view of a composite drainage structure suitable for use in a high fines content sand formation to resist liquefaction in accordance with the present invention;
fig. 2 is a schematic structural diagram of a geotechnical drainage assembly in a composite drainage structure suitable for high-fine-content sand layer liquefaction resistance according to the invention;
FIG. 3 is a schematic structural diagram of square arrangement of gravel piles in a composite drainage structure suitable for a high-fine-grain-content sand layer to resist liquefaction according to the invention;
FIG. 4 is a schematic structural view of a composite drainage structure suitable for a high-fine-grain-content sand layer and resistant to liquefaction, in which gravel piles are arranged in regular triangles;
fig. 5 is a schematic construction flow diagram of a gravel pile and a geotechnical drainage assembly in the construction method of the composite drainage structure with high fine grain content sand layer liquefaction resistance according to the invention;
FIG. 6 is a schematic structural diagram of a double-layer pipe vibrating pipe in the construction method of the anti-liquefaction composite drainage structure for the sand layer with high fine grain content, according to the invention;
FIG. 7 is a schematic structural diagram of a first valve in the construction method of the composite drainage structure for preventing liquefaction of a high-fine-grain-content sand layer according to the invention;
FIG. 8 is a schematic structural diagram of a penetration cone head in the construction method of the anti-liquefaction composite drainage structure for the high-fine-grain-content sand layer according to the invention;
fig. 9 is a top view of a penetration cone in the construction method of the composite drainage structure for preventing liquefaction of a high fine content sand layer according to the present invention.
In the figure, 1-gravel pile, 2-gravel cushion, 3-geotechnical drainage component, 31-drainage pipe, 311-drainage pore, 32-geotechnical cloth, 33-supporting rod, 34-connecting plate, 35-anchoring end, 4-double-layer pipe vibrating pipe, 41-first outer sleeve, 411-feeding hole, 42-first inner sleeve, 43-top plate, 44-first valve, 441-bolt, 442-semi-annular movable plate, 45-second valve, 46-penetrating conical head, 461-second inner sleeve, 462-blade, 463-second outer sleeve, 5-foundation to be treated and 6-excitation device.
Detailed Description
In order to make the objects, technical solutions and advantages of the embodiments of the present invention clearer, the technical solutions in the embodiments of the present invention will be clearly and completely described below with reference to the drawings in the embodiments of the present invention, and it is obvious that the described embodiments are some, but not all, embodiments of the present invention. The components of embodiments of the present invention generally described and illustrated in the figures herein may be arranged and designed in a wide variety of different configurations.
Thus, the following detailed description of the embodiments of the present invention, presented in the figures, is not intended to limit the scope of the invention, as claimed, but is merely representative of selected embodiments of the invention. All other embodiments, which can be derived by a person skilled in the art from the embodiments given herein without making any creative effort, shall fall within the protection scope of the present invention.
It should be noted that: like reference numbers and letters refer to like items in the following figures, and thus, once an item is defined in one figure, it need not be further defined and explained in subsequent figures. Meanwhile, in the description of the present invention, the terms "first", "second", and the like are used only for distinguishing the description, and are not to be construed as indicating or implying relative importance.
It is noted that, herein, relational terms such as first and second, and the like may be used solely to distinguish one entity or action from another entity or action without necessarily requiring or implying any actual such relationship or order between such entities or actions. Also, the terms "comprises," "comprising," or any other variation thereof, are intended to cover a non-exclusive inclusion, such that a process, method, article, or apparatus that comprises a list of elements does not include only those elements but may include other elements not expressly listed or inherent to such process, method, article, or apparatus. Without further limitation, an element defined by the phrase "comprising an … …" does not exclude the presence of other identical elements in a process, method, article, or apparatus that comprises the element.
In the description of the present invention, it should be noted that the terms "upper", "lower", "inside", "outside", and the like indicate orientations or positional relationships based on the orientations or positional relationships shown in the drawings or orientations or positional relationships conventionally put in use of products of the present invention, and are only for convenience of description and simplification of description, but do not indicate or imply that the devices or elements referred to must have specific orientations, be constructed in specific orientations, and be operated, and thus, should not be construed as limiting the present invention.
Referring to fig. 1 and 2, fig. 1 is a schematic structural view of a composite drainage structure suitable for high-fine-content sand liquefaction prevention according to the present invention, and fig. 2 is a schematic structural view of a geotechnical drainage component in the composite drainage structure suitable for high-fine-content sand liquefaction prevention according to the present invention. The utility model provides a be suitable for anti liquefied composite drainage structure of high particulate content sand bed, includes to lay a plurality of gravel piles 1 in needing to handle ground 5 and to lay in the rubble bed course 2 that needs to handle the 5 surfaces of ground, is equipped with geotechnological drainage component 3 in the gravel pile 1, and in the rubble bed course 2 was inserted on the top of geotechnological drainage component 3, geotechnological drainage component 3 included drain pipe 31 and the geotechnological cloth 32 of parcel on drain pipe 31 lateral wall, has seted up drainage hole 311 on the drain pipe 31.
Referring to fig. 3 and 4 in combination, fig. 3 is a schematic structural diagram of gravel piles arranged in a square shape in the composite drainage structure suitable for high-fine-content sand layer anti-liquefaction of the present invention, and fig. 4 is a schematic structural diagram of gravel piles arranged in a regular triangle shape in the composite drainage structure suitable for high-fine-content sand layer anti-liquefaction of the present invention. In practical use, the drain pipe 31 is positioned inside the gravel pile 1, the geotechnical cloth 32 is wrapped on the outer side wall of the drain pipe 31, the drain pipe 31 serves as a main drainage channel and can provide constant vertical drainage clearance, the phenomenon that the drainage performance of the peripheral gravel pile 1 is remarkably reduced due to silting up and cannot meet the requirement for ultra-pore water pressure dissipation under the action of an earthquake is avoided, the gravel pile 1 serves as a reverse filter layer of the geotechnical drainage assembly 3 and prevents fine particles in an easily liquefied sand layer foundation from silting up and blocking the outer layer of the geotechnical drainage assembly 3 under the action of water flow, the service life of the drain pipe 31 can be prolonged, and the durability is high. The geotextile 32 wrapped on the outer side wall of the drain pipe 31 plays a role in further preventing sandy soil particles passing through the gravel pile 1 from entering the drain pipe 31, and can prevent sandy soil particles from entering the drain pipe 31 through pores and depositing at the bottom of the drain pipe 31 under the action of pore pressure or water flow during the long-term use of the drain pipe 31, so that the drainage section is reduced. The gravel cushion layer 2 on the surface of the foundation 5 to be treated plays a role of bearing water in the geotechnical drainage assembly 3 and is used as a horizontal drainage channel, so that the composite drainage structure suitable for the anti-liquefaction composite drainage structure of the sand layer with high fine grain content can quickly dissipate pore pressure under the action of an earthquake, and further plays a role in drainage and anti-liquefaction. In an embodiment, the gravel piles 1 are arranged in a square or regular triangle.
In an embodiment, the geotechnical drainage assembly 3 further comprises a support rod 33, a connection plate 34 and an anchoring end 35 in an inverted cone shape, wherein the anchoring end 35 is open at the top end and hollow inside, one end of the support rod 33 is arranged at the bottom end in the anchoring end 35, the other end of the support rod 33 is arranged on the connection plate 34, and the bottom end of the drainage pipe 31 is arranged in the anchoring end 35 and connected with the connection plate 34. An anchoring end 35 is added at the bottom end of the drain pipe 31, and when the drain pipe 31 is lowered for construction, the anchoring end 35 can be anchored with the gravel pile 1 to relatively fix the position of the drain pipe 31. In one embodiment, the connecting plate 34 is screwed to the bottom end of the drain pipe 31, so that the connection between the connecting plate 34 and the bottom end of the drain pipe 31 is stable and reliable. In one embodiment, the geotechnical drainage component 3 is inserted into the gravel cushion layer 2 at a distance of 10 cm-20 cm.
In one embodiment, the opening ratio of the drain pipe 31 is 20% to 25%, and the inner diameter of the drain pipe 31 is 100mm to 120 mm. Furthermore, the drain pipe 31 can be made of corrugated pipe or PVC pipe, the inner diameter of the drain pipe 31 is 100 mm-120 mm, and the wall thickness of the drain pipe 31 is 5 mm. In one embodiment, the geotextile 32 is woven from synthetic fibers, and the geotextile 32 has a permeability coefficient of 10-1cm/s to 10-2 cm/s. Further, the geotextile 32 has a thickness of 10 mm.
Referring to fig. 5 and 6 in combination, fig. 5 is a schematic construction flow diagram of a gravel pile and a geotechnical drainage assembly in the construction method of the composite drainage structure for preventing liquefaction of a sand layer with high fine grain content according to the present invention, and fig. 6 is a schematic structural diagram of a double-layer pipe vibration pipe in the construction method of the composite drainage structure for preventing liquefaction of a sand layer with high fine grain content according to the present invention. In order to facilitate installation of the composite drainage structure suitable for the anti-liquefaction of the sand layer with high fine grain content and improve the construction efficiency of the composite drainage structure suitable for the anti-liquefaction of the sand layer with high fine grain content, the invention also provides a construction method of the composite drainage structure suitable for the anti-liquefaction of the sand layer with high fine grain content, the construction method adopts the double-layer pipe vibrating pipe 4 for construction, the double-layer pipe vibrating pipe 4 comprises a first outer sleeve 41, a first inner sleeve 42 and a top plate 43, the top end of the first outer sleeve 41 is arranged on the top plate 43, the upper part of the outer side wall of the first outer sleeve 41 is provided with a feed inlet 411, the first inner sleeve 42 is arranged in the first outer sleeve 41, the top end of the first inner sleeve is arranged on the top plate 43, a feed delivery channel is formed between the first inner sleeve 42 and the first outer sleeve 41, the lower part of the feed delivery channel is provided with a first valve 44 for opening and closing the feed delivery channel, the bottom end of the first inner sleeve 42 is provided with a second valve 45 for opening and closing the bottom end of the first inner sleeve 42, the top plate 43 is opened to communicate with the inside of the first inner tube 42. The first inner sleeve 42 is used for installing the geotechnical drainage assembly 3, and an annular conveying channel between the first inner sleeve 42 and the first outer sleeve 41 is used for gravel installation to form the gravel pile 1.
The construction method of the anti-liquefaction composite drainage structure suitable for the high-fine-grain-content sand layer comprises the following steps:
s1, determining construction hole positions;
s2, constructing the gravel pile 1 and the geotechnical drainage component 3 at each construction hole site;
s21, fixing the double-layer tube vibrating tube 4 by using a guide frame, so that the double-layer tube vibrating tube 4 is aligned to a construction hole position;
s22, sinking the double-layer tube 4 to a predetermined design depth by the vibration excitation device 6 when the first valve 44 and the second valve 45 are closed;
s23, opening the first valve 44 and the second valve 45, stopping the vibration excitation device 6 and placing the geotechnical drainage assembly 3 into the first inner sleeve 42, so that the geotechnical drainage assembly 3 slides to a preset design depth along the first inner sleeve 42;
s24, penetrating crushed stone from the feeding hole 411 on the first outer sleeve 41 until the crushed stone reaches a set filling height in the conveying channel;
s25, pulling up the double-layer tube vibrating tube 4 to the ground through the vibration excitation equipment 6 while vibrating, and continuously injecting gravel from the feeding hole 411 on the first outer sleeve 41 in the process of pulling up the double-layer tube vibrating tube 4 to form a gravel pile 1;
and S3, paving the gravel cushion layer 2.
In the step S1, the foundation 5 to be processed is surveyed, the reinforcement range and the liquefaction resistance range of the foundation 5 to be processed are determined, a plurality of construction holes are determined in the liquefaction resistance range, and the construction holes are lofted, wherein the construction holes are used for constructing the gravel pile 1 and the geotechnical drainage assembly 3. The construction hole positions are arranged in a square shape or a regular triangle shape.
In step S2, the gravel pile 1 and the soil drainage module 3 are constructed at the construction sites in sequence.
Specifically, in step S21, the double-layer pipe vibrating pipe 4 is moved to correspond to the construction hole position, and the double-layer pipe vibrating pipe 4 is fixed by the guide frame, where the double-layer pipe vibrating pipe 4 is perpendicular to the surface of the foundation. The vibration excitation device 6 is provided with a vibration hammer which is connected with the top plate 43 of the double-layer tube vibrating tube 4 so as to drive the double-layer tube vibrating tube 4 to vibrate through the vibration hammer, and the double-layer tube vibrating tube 4 is sunk into the foundation 5 to be treated.
Referring to fig. 7, fig. 7 is a schematic structural diagram of a first valve in the construction method of the composite drainage structure suitable for the high-fine-grain-content sand layer to resist liquefaction according to the present invention. In the step S22, the first valve 44 and the second valve 45 are closed to prevent soil in the foundation 5 from entering the material conveying channel of the double-layer vibrating pipe 4 and the first inner sleeve 42 when the double-layer vibrating pipe 4 sinks. In an embodiment, the first shutter 44 includes two pins 441 and two semi-annular movable plates 442, the two pins 441 are symmetrically disposed on the first inner sleeve 42, the two semi-annular movable plates 442 are disposed on two sides of the first inner sleeve 42, and two ends of each semi-annular movable plate 442 are respectively rotatably connected to the two pins 441 through hinges, and/or the second shutter 45 includes a baffle rotatably connected to a bottom end of the first inner sleeve 42 through a hinge. Specifically, the semi-annular movable plate 442 can rotate upward to a horizontal position relative to the first inner sleeve 42 to close the feeding passage, and can also rotate downward to a vertical position relative to the first inner sleeve 42 to open the feeding passage. The shutter can be rotated upward relative to the first inner sleeve 42 to a horizontal position to close the opening at the bottom end of the first inner sleeve 42, and can also be rotated downward relative to the first inner sleeve 42 to an upright position to open the opening at the bottom end of the first inner sleeve 42. When the double-layer tube shakes pipe 4 and sinks, under the pressure effect of the soil body, semi-annular movable plate 442 upwards rotates to the horizontal state for the closed defeated material passageway of two semi-annular movable plates 442 seals defeated material passageway, and same baffle upwards rotates to the horizontal state, makes the opening of the first interior sleeve pipe 42 bottom of baffle closure, seals the opening of first interior sleeve pipe 42 bottom, avoids soil to get into defeated material passageway and first interior sleeve pipe 42 in. When the first valve 44 and the second valve 45 are required to be opened, the double-layer sleeve is only required to be lifted upwards for a certain distance, and at the moment, the semi-annular movable plate 442 and the baffle plate can rotate downwards to be in a vertical state under the action of self gravity, so that the material conveying channel and the opening at the bottom end of the first inner sleeve 42 are opened.
And then starting the excitation equipment 6, and inserting the double-layer pipe vibration pipe 4 into the foundation 5 to be treated under the action of gravity and vibration, wherein the insertion depth is the pile length of the gravel pile 1. Preferably, before the double-layer pipe vibrating pipe 4 sinks, marks can be made on the double-layer pipe vibrating pipe 4 according to the designed pile length so as to control the sinking depth of the double-layer pipe vibrating pipe 4.
Further, in the step of sinking the double-pipe vibrating tube 4 to a predetermined design depth by the vibration exciting device 6, the double-pipe vibrating tube 4 is sunk 0.5m and left to vibrate for 30 seconds. In the process of sinking the double-layer pipe vibrating pipe 4, the sand layer of the peripheral foundation is vibrated and compacted simultaneously, and the liquefaction resistance strength of the reinforced sand layer is improved.
Referring to fig. 8 and 9 in combination, fig. 8 is a schematic structural diagram of a penetration cone in a construction method of the composite drainage structure suitable for high-fine-content sand layer anti-liquefaction according to the present invention, and fig. 9 is a top view of the penetration cone in the construction method of the composite drainage structure suitable for high-fine-content sand layer anti-liquefaction according to the present invention. In an embodiment, in order to facilitate the double-tube casing to sink into the foundation 5 to be treated, the double-tube casing further includes a penetration cone 46, the penetration cone 46 includes a second inner tube 461 and a plurality of blades 462 arranged on an outer side wall of the second inner tube 461 at intervals along a circumferential direction of the second inner tube 461, the second inner tube 461 is arranged coaxially with the first inner tube 42, a cross section of the second inner tube 461 has a same size as a cross section of the first inner tube 42, the second shutter 45 is arranged at a bottom end of the second inner tube 461, and the plurality of blades 462 are arranged at a bottom end of the first outer tube 41. This setting has strengthened the sheathed tube penetrability of double tube, ability and the degree of penetration of breaking ground for the double tube sleeve pipe pierces easily and need handle ground 5 in, sleeve pipe 461 bottom is the plane in the second simultaneously, can play directional effect, keeps perpendicularly when making the double tube sleeve pipe penetrate the ground. In one embodiment, in order to facilitate the installation of the penetration cone 46 on the first outer sleeve 41, the penetration cone 46 further includes a second outer sleeve 463, the second outer sleeve 463 is sleeved on the outer side of the second inner sleeve 461 and is disposed at the top end of the plurality of blades 462, the blades 462 are in the shape of right trapezoid, the lower bottom of the right trapezoid of the blades 462 is connected with the outer side wall of the second inner sleeve 461, the right waist of the right trapezoid of the blades 462 is connected with the second outer sleeve 463, and the second outer sleeve 463 is detachably disposed at the bottom end of the first outer sleeve 41. The second outer sleeve 463 is connected with the first outer sleeve 41, so that the penetrating bit 46 is convenient to disassemble and assemble. In an embodiment, a threaded connection may be used between the second outer sleeve 463 and the first outer sleeve 41, such that the connection between the second outer sleeve 463 and the first outer sleeve 41 is secure.
In the step S23, the double-layer sleeve is lifted up by the excitation device 6 for a certain distance, and the semi-annular movable plate 442 and the baffle plate can rotate downward to the vertical state under the action of the lifting gravity, so as to open the feeding passage and the opening at the bottom end of the first inner sleeve 42, i.e. open the first shutter 44 and the second shutter 45. And then stopping the excitation equipment 6, putting the geotechnical drainage assembly 3 into the first inner sleeve 42 from the opening of the top plate 43, and enabling the geotechnical drainage assembly 3 to slide into the designed depth by the bottom end of the first inner sleeve 42 of the self-weight slideway through the geotechnical drainage assembly 3. In one embodiment, a valve is provided at the opening of the top plate 43. When the double-layer tube vibrating tube 4 sinks, the valve at the opening of the top plate 43 is closed, and impurities are prevented from entering the first inner sleeve 42 from the opening of the top plate 43. When the geotechnical drainage assembly 3 needs to be put in, the valve at the opening of the top plate 43 is opened.
In step S24, after the geotechnical drainage module 3 slides into the designed depth, the gravel is injected from the inlet 411 of the first outer casing 41, and the gravel stops injecting when the gravel reaches the set filling height in the material transportation channel, for example, when the gravel is filled up to one third of the length of the double-layer vibrating tube 4.
In the above step S25, the double-pipe vibrating tube 4 is pulled up to the ground by the vibration excitation device 6 while vibrating, and the gravel is continuously injected from the inlet 411 of the first outer sleeve 41 during the pulling up of the double-pipe vibrating tube 4, so as to form the gravel pile 1 around the geotechnical drainage module 3. In an embodiment, the geotechnical drainage assembly 3 further comprises a support rod 33, a connecting plate 34 and an anchoring end 35 in an inverted cone shape, the anchoring end 35 is open at the top end and hollow inside, one end of the support rod 33 is arranged at the bottom end in the anchoring end 35, the other end is arranged on the connecting plate 34, and the bottom end of the drainage pipe 31 is arranged in the anchoring end 35 and connected with the connecting plate 34. When the double-layer pipe vibrating tube 4 is pulled up, the anchor end 35 can be buried by the broken stones, and the situation that the surface of the foundation 5 to be treated is also brought out of the geotechnical drainage assembly 3 due to the friction force generated when the double-layer pipe vibrating tube 4 is pulled up is avoided.
Further, before the step of pulling up the double-layer pipe vibrating tube 4 to the ground while vibrating by the vibration excitation device 6, the method further comprises the following steps:
s25a, driving the double-layer tube vibrating tube 4 to vibrate for 1 minute through the vibration excitation equipment 6;
in the step of pulling up the double-layer tube vibrating tube 4 to the ground while vibrating by the vibration excitation equipment 6, the double-layer tube vibrating tube 4 is kept vibrating for 10-20 seconds every time the double-layer tube vibrating tube 4 is lifted by 0.5-1 m.
Before shaking the pipe 4 with the double tube and pulling out, shake the pipe 4 vibration 1 minute through the double tube of excitation equipment 6 drive, can shake the rubble of intraductal 4 of double tube and vibrate the density, equally, shake the in-process that the pipe 4 pulled out with the double tube, the double tube shakes pipe 4 and every promotes 0.5m ~ 1m, stay shake 10 seconds ~ 20 seconds, can shake the density with the rubble that penetrates into in the double tube 4 of shaking, in order to form rubble pile 1, and can have consolidated need to handle ground 5 through rubble pile 1, the foundation bearing capacity has been improved, and then can be directly at 2 surface construction road surface structures on rubble bed course.
In the step S3, the gravel cushion layer 2 is laid on the surface of the foundation 5 to be treated according to the designed thickness of the gravel cushion layer 2, the gravel cushion layer 2 should be laid layer by layer, and the thickness of each layer should not exceed 300 mm. After the construction is finished, the laid gravel cushion layer 2 is used as a horizontal drainage channel, plays a role in bearing water in the geotechnical drainage assembly 3, can quickly dissipate pore pressure under the action of an earthquake, and further plays a role in drainage and liquefaction resistance. Preferably, the geotechnical drainage component 3 is inserted into the gravel cushion layer 2 at a distance of 10-20 cm.
Compared with the prior art, the invention has the beneficial effects that:
(1) the geotechnical drainage component 3 is used as a main drainage channel, so that constant vertical drainage clearance can be provided, and the phenomenon that the drainage performance of peripheral gravel piles 1 is remarkably reduced due to siltation and the requirement for ultra-pore water pressure dissipation under the action of an earthquake cannot be met is avoided;
(2) the gravel piles 1 around the geotechnical drainage component 3 can be used as a reverse filter layer of the geotechnical drainage component 3, so that fine particles in an easily liquefied sand bed foundation are prevented from clogging the outer layer of the geotechnical drainage component 3 under the action of water flow;
(3) compared with the crushed stone material with the same volume, the geotechnical drainage component 3 has low cost, and compared with the method of simply using the crushed stone pile 1 as a drainage channel under the condition of the same replacement rate, the method can obviously reduce the manufacturing cost of anti-liquefaction foundation treatment;
(4) the drainage anti-liquefaction system consisting of the gravel pile 1, the geotechnical drainage component 3 and the surface gravel cushion layer 2 can quickly dissipate pore pressure under the action of an earthquake, and plays a role in drainage anti-liquefaction.
The above description is only a preferred embodiment of the present invention, and is not intended to limit the present invention in any way, so that any simple modification, equivalent change and modification made to the above embodiment according to the technical spirit of the present invention will still fall within the scope of the technical solution of the present invention without departing from the content of the technical solution of the present invention.
Claims (10)
1. The utility model provides a be suitable for anti liquefied composite drainage structure of high particulate content sand bed, its characterized in that, including lay a plurality of rubble piles in the foundation that need be handled and lay the rubble bed course on need handling the foundation surface, be equipped with geotechnological drainage subassembly in the rubble pile, the top of geotechnological drainage subassembly is inserted in the rubble bed course, geotechnological drainage subassembly includes drain pipe and the geotechnological cloth of parcel on the drain pipe lateral wall, the drainage hole has been seted up on the drain pipe.
2. The composite drainage structure adapted for use in high fine content sand to resist liquefaction of claim 1, wherein the geotechnical drainage assembly further comprises a support rod, a connecting plate and an anchoring end in the shape of an inverted cone, the anchoring end being open at the top end and hollow inside, the support rod being disposed at the bottom end inside the anchoring end at one end and on the connecting plate at the other end, the drainage pipe being disposed at the bottom end inside the anchoring end and connected to the connecting plate.
3. The composite drainage structure adapted for use with a high fines content sand layer to resist liquefaction of claim 1, wherein the drainpipe has an open porosity of 20% to 25% and an internal diameter of 100mm to 120 mm.
4. The composite drainage structure adapted to resist liquefaction and used for high fine content sand layer as claimed in claim 1, wherein said geotextile is woven from synthetic fibers and has a water permeability coefficient of 10-1cm/s～10-2cm/s。
5. The composite drainage structure resistant to liquefaction for high fine content sand layers as in claim 1, wherein said gravel piles are arranged in a square or regular triangle.
6. The construction method of the composite drainage structure suitable for the anti-liquefaction of the high-fine-grain-content sand layer is characterized in that a double-layer vibrating pipe is adopted for construction, the double-layer vibrating pipe comprises a first outer sleeve, a first inner sleeve and a top plate, the top end of the first outer sleeve is arranged on the top plate, a feed inlet is formed in the upper portion of the outer side wall of the first outer sleeve, the first inner sleeve is arranged in the first outer sleeve, the top end of the first inner sleeve is arranged on the top plate, a material conveying channel is formed between the first inner sleeve and the first outer sleeve, a first valve used for opening and closing the material conveying channel is arranged at the lower portion of the material conveying channel, a second valve used for opening and closing the bottom end opening of the first inner sleeve is arranged at the bottom end of the first inner sleeve, and an opening communicated with the interior of the first inner sleeve is formed in the top plate;
the construction method comprises the following steps:
s1, determining construction hole positions;
s2, constructing gravel piles and geotechnical drainage assemblies at the construction hole sites;
s21, fixing the double-layer pipe vibrating pipe by using a guide frame, so that the double-layer pipe vibrating pipe is aligned to a construction hole position;
s22, sinking the double-layer pipe vibrating tube to a preset design depth through vibration excitation equipment under the condition that the first valve and the second valve are closed;
s23, opening the first valve and the second valve, stopping the vibration excitation equipment and placing the geotechnical drainage assembly into the first inner sleeve pipe, so that the geotechnical drainage assembly slides to a preset design depth along the first inner sleeve pipe;
s24, penetrating broken stones from a feeding hole in the first outer sleeve until the broken stones reach a set filling height in the conveying channel;
s25, pulling the double-layer tube vibrating tube to the ground while vibrating through the vibration excitation equipment, and continuously injecting gravel from a feed inlet on the first outer sleeve in the process of pulling the double-layer tube vibrating tube to form a gravel pile;
and S3, paving a gravel cushion.
7. The construction method of the composite drainage structure applicable to the liquefaction resistance of the high-fine-grain-content sand layer, according to claim 6, wherein the double-layer pipe sleeve further comprises a penetration conical head, the penetration conical head comprises a second inner sleeve and a plurality of blades arranged on the outer side wall of the second inner sleeve at intervals along the circumferential direction of the second inner sleeve, the second inner sleeve is coaxially arranged with the first inner sleeve, the cross section of the second inner sleeve has the same size as that of the first inner sleeve, the second valve is arranged at the bottom end of the second inner sleeve, and the plurality of blades are arranged at the bottom end of the first outer sleeve.
8. The construction method of the composite drainage structure suitable for the anti-liquefaction of the high-fine-grain-content sand layer as claimed in claim 6, wherein the first valve comprises two pins and two semi-annular movable plates, the two pins are symmetrically arranged on the first inner sleeve, the two semi-annular movable plates are arranged on two sides of the first inner sleeve, two ends of each semi-annular movable plate are rotatably connected to the two pins through hinges respectively, and/or the second valve comprises a baffle plate, and the baffle plate is rotatably connected to the bottom end of the first inner sleeve through hinges.
9. The method for constructing a composite drainage structure suitable for use in a high fine content sand layer to resist liquefaction according to claim 6, wherein in the step of sinking the double-layer pipe vibrating pipe to a predetermined design depth by using an excitation device, the double-layer pipe vibrating pipe is sunk 0.5m and left to vibrate for 30 seconds.
10. The method for constructing a composite drainage structure suitable for the liquefaction resistance of a sand layer with high fine grain content as claimed in claim 6, wherein before the step of pulling up the double-layer pipe vibrating pipe to the ground while vibrating by the vibration excitation device, the method further comprises the following steps:
driving the double-layer tube vibration tube to vibrate for 1 minute through the vibration excitation equipment;
and in the step of pulling up the double-layer tube vibrating tube to the ground while vibrating through the vibration excitation equipment, the double-layer tube vibrating tube is kept vibrating for 10-20 seconds every time the double-layer tube vibrating tube is lifted by 0.5-1 m.
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| CN202210180100.1A CN114457782B (en) | 2022-02-25 | 2022-02-25 | Anti-liquefaction composite drainage structure suitable for high-fine-grain-content sand layer and construction method of anti-liquefaction composite drainage structure |
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| CN202210180100.1A CN114457782B (en) | 2022-02-25 | 2022-02-25 | Anti-liquefaction composite drainage structure suitable for high-fine-grain-content sand layer and construction method of anti-liquefaction composite drainage structure |
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| CN112627162A (en) * | 2020-12-22 | 2021-04-09 | 中建安装集团有限公司 | Drainage stiffening core composite pile based on geopolymer grouting and construction method thereof |
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| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| CN101886545A (en) * | 2010-07-05 | 2010-11-17 | 北京科技大学 | Method for treating bottom heave of soft rock roadway by using micro broken stone pipe cast pile |
| CN103243703A (en) * | 2013-04-18 | 2013-08-14 | 浙江大学宁波理工学院 | Soft soil consolidation processing method by utilizing hard hollow tubes with pores reserved on side walls |
| CN204059332U (en) * | 2014-05-30 | 2014-12-31 | 海南通程建筑工程有限公司 | A kind of concrete precast pipe pile and piling prepressing Soft Ground device |
| CN207934023U (en) * | 2017-12-19 | 2018-10-02 | 四川鑫益诚仿古建设有限公司 | A kind of adjustable building stake |
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