CN111827326B - Rapid water lowering device and method for multi-aquifer-multi-aquifer penetrating submerged well - Google Patents
Rapid water lowering device and method for multi-aquifer-multi-aquifer penetrating submerged well Download PDFInfo
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- CN111827326B CN111827326B CN202010561996.9A CN202010561996A CN111827326B CN 111827326 B CN111827326 B CN 111827326B CN 202010561996 A CN202010561996 A CN 202010561996A CN 111827326 B CN111827326 B CN 111827326B
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- E—FIXED CONSTRUCTIONS
- E02—HYDRAULIC ENGINEERING; FOUNDATIONS; SOIL SHIFTING
- E02D—FOUNDATIONS; EXCAVATIONS; EMBANKMENTS; UNDERGROUND OR UNDERWATER STRUCTURES
- E02D19/00—Keeping dry foundation sites or other areas in the ground
- E02D19/06—Restraining of underground water
- E02D19/10—Restraining of underground water by lowering level of ground water
Abstract
The invention relates to a cross-layer submerged well rapid precipitation device and a method for a multi-aquifer-multi-waterproof layer, wherein in the multi-aquifer-multi-waterproof layer system, a low-permeability aquifer, a waterproof layer and a high-permeability aquifer sequentially exist in a soil layer partitioned by a waterproof curtain from top to bottom; the rapid dewatering device comprises a shallow layer dewatering well for draining a low-permeability aquifer, a depressurization-dewatering well for draining a high-permeability aquifer and a cross-layer submersible well arranged around the depressurization-dewatering well, wherein the cross-layer submersible well is provided with a drill hole which penetrates through the low-permeability aquifer, the high-permeability aquifer and a middle water barrier and is used for communicating the low-permeability aquifer and the high-permeability aquifer to form up-down water channeling. Compared with the prior art, the process of introducing the cross-layer submersible well into the waterproof curtain multi-aquifer-multi-waterproof-layer system can remarkably accelerate the drainage process, and can provide a new idea for a foundation pit dewatering construction process.
Description
Technical Field
The invention belongs to the technical field of geological engineering, geotechnical engineering and underground engineering, relates to a method for accelerating precipitation by arranging a cross-layer drilling hole in a precipitation construction process of an engineering field, and particularly relates to a cross-layer submerged well rapid precipitation device and method for a multi-aquifer-multi-water-barrier layer.
Background
In the construction environment with higher underground water level, well point dewatering is an important technical measure in the construction of earthwork, foundation and foundation engineering, can drain water in foundation soil, promote soil consolidation, improve foundation strength, simultaneously can reduce soil slope soil lateral displacement and settlement, stabilize side slope, eliminate sand running, reduce uplift of foundation soil, avoid the influence of underground water in the construction of foundation and foundation engineering below natural underground water, provide drier construction conditions, reduce earthwork amount, shorten construction period, improve engineering quality and ensure construction safety. When the engineering site rainfall is specifically designed, the shallow diving aquifer is generally drained, and the pressure-bearing aquifer in deeper places is subjected to pressure reduction rainfall. In the prior art, the mode of respectively arranging a drying well and a pressure reduction well in a diving aquifer and a bearing aquifer is generally adopted for precipitation of an engineering field, namely, the mode of layering precipitation is adopted. However, the distribution of the soil layers of the actual engineering field may be complex, for example, if there are multiple aquifers and multiple water barriers, the permeability of the aquifers may also be greatly different, if the permeability of the aquifer of the upper layer is poor, the drainage effect of the drainage well is not obvious, and the drainage well is not coordinated with the operation of the depressurization-drainage well of the lower layer, which may cause the problems of slow precipitation speed and influence on the construction period. At present, researches on how to accelerate the precipitation rate of a multi-aquifer-multi-waterproof-layer system are urgently needed.
Disclosure of Invention
The multi-aquifer-water-barrier system requires that two aquifers exist in a soil layer separated by the waterproof curtain, the aquifers can be divided by the water-barrier, the upper aquifer is a soil layer with low permeability, the lower aquifer is a soil layer with good permeability, the depressurization-dewatering well has good drainage effect when pumping and draining the lower aquifer, but the drainage effect of the upper dewatering well is poor, and the system only is provided with the depressurization-dewatering well and the upper dewatering well to reduce water so as to influence the integral precipitation speed of the foundation pit.
The invention aims to overcome the defects of the prior art and provide a device and a method for quickly lowering water in a multi-aquifer-multi-water-barrier penetrating submerged well.
The purpose of the invention can be realized by the following technical scheme:
the invention provides a layer-crossing submerged well rapid precipitation device for a multi-aquifer-multi-waterproof layer, wherein in the multi-aquifer-multi-waterproof layer system, a low-permeability aquifer, a waterproof layer and a high-permeability aquifer sequentially exist in a soil layer partitioned by a waterproof curtain from top to bottom; the rapid dewatering device comprises a shallow layer dewatering well for draining a low-permeability aquifer, a depressurization-dewatering well for draining a high-permeability aquifer and a cross-layer submersible well arranged around the depressurization-dewatering well, wherein the cross-layer submersible well is provided with a drill hole which penetrates through the low-permeability aquifer, the high-permeability aquifer and a middle water barrier and is used for communicating the low-permeability aquifer and the high-permeability aquifer to form up-down water channeling.
In the invention, the pressure reduction-drainage well and the shallow drainage well are designed in number and size according to two aquifers for layered dewatering (traditional dewatering mode), so that the dewatering requirements of engineering construction are met. Additionally arranging drill holes around the pressure reduction-drainage composite well, wherein the drill holes are good in permeability, and the drill holes are used as water-permeable stratum-penetrating submerged wells to communicate an upper aquifer with a lower aquifer and serve as hydraulic channels of the two aquifers to promote drainage of the upper aquifer.
Preferably, the sand filling is arranged near the depth of the water isolation layer in the drill hole, and meanwhile, the backfill clay hole sealing is arranged at the upper part of the drill hole.
Preferably, the borehole is provided with a counterbore at about the depth of the water barrier (interface between two aquifers).
Preferably, the depth of the water barrier layer is in a depth range including the whole water barrier layer and the water-containing layers on the upper and lower sides of the water barrier layer.
Preferably, the cross-over laterals are evenly arranged around the depressurization-drainage wells.
Preferably, 2-3 penetrating submerged wells are arranged around the depressurization-drainage well.
In the invention, in order to ensure that the hydraulic connection between the two aquifers is maintained, sand can be backfilled near the depth of the water isolation layer in the drill hole, and meanwhile, clay is backfilled at the upper part of the drill hole to seal the hole, so that the low-permeability soil in the aquifer at the upper layer is prevented from blocking a water seepage channel, and the high permeability at the lower part of the drill hole is ensured. The drill hole is used as a cross-layer submerged well, filter pipes are not required to be arranged in the drill hole for drainage, construction cost is greatly reduced, and proper hole expansion is needed near the depth of an interface (a water-resisting layer) of two aquifers.
The invention also provides a method for rapidly dewatering a multi-aquifer-multi-water-barrier penetrating submerged well, which adopts the rapid dewatering device and comprises the following steps:
determining that a low-permeability aquifer, a water-resisting layer and a high-permeability aquifer exist in sequence from top to bottom in a soil layer of which the stratum distribution conforms to a multi-aquifer-multi-water-resisting layer system and is separated by a water-stopping curtain, and determining that the precipitation rate of the low-permeability aquifer on which the engineering site precipitation exists is low;
respectively arranging a cross-layer submerged well near each pressure reducing-drainage well in the drilling process of the pressure reducing-drainage wells to form water channeling up and down;
in the process of construction of the cross-layer submerged well, when a hole is drilled to the depth near the depth of a water-resisting layer (an interface of two water-bearing layers), hole expansion is carried out, and after the hole is drilled, sand backfill and clay backfill are timely carried out to seal the hole, so that hole collapse is prevented;
in the precipitation process, along with the high permeability aquifer of lower floor draws water fast, forms the flood head difference, and the low permeability aquifer normal water of upper strata passes through the high permeability aquifer of drilling supply lower floor, realizes accelerating drainage process.
Preferably, no filter pipe is provided in the borehole of the cased laterals.
Compared with the prior art, the invention has the following beneficial effects:
the invention can utilize the cross-layer submersible well to economically and rapidly pump water through the depressurization-drainage composite well to accelerate the upper layer drainage speed under the condition that the upper layer aquifer drainage is not smooth. When the engineering site is excavated and constructed, for the conditions of large excavation depth and high underground water level, the condition that the water level is reduced below the excavation surface is a necessary condition for smoothly excavating the foundation pit, if the problems that the precipitation effect cannot meet the requirement and the construction period is delayed exist in the common precipitation method of the low-permeability aquifer, the drainage process can be obviously accelerated by introducing the layer-penetrating submerged well into the water-stopping curtain multi-aquifer-multi-aquifer system, and a new idea can be provided for the foundation pit precipitation construction process.
Drawings
FIG. 1 is a schematic view of the structure of the rapid precipitation device of the present invention;
fig. 2 is a schematic plan view of the rapid precipitation device of the present invention.
In the figure, 1 is a low permeability aquifer, 2 is a high permeability aquifer, 3 is a water barrier, 4 is a depressurization-dewatering well, 5 is a shallow dewatering well, 6 is a penetrating submerged well, 7 is a borehole, 8 is backfill sand, 9 is a hole enlargement, 10 is backfill clay, 11 is a multi-aquifer-water barrier system, and 12 is a water curtain.
Detailed Description
The invention is described in detail below with reference to the figures and specific embodiments.
Example 1
As shown in fig. 1, in a multi-aquifer-multi-barrier system 11, a low-permeability aquifer 1, a barrier 3, and a high-permeability aquifer 2 (the high-permeability aquifer 2 has a high permeability, and the low-permeability aquifer 1 has a low permeability) are sequentially present from top to bottom in a layer partitioned by a waterproof curtain 12. The pressure reduction-drainage well has good drainage effect when a lower aquifer is pumped and drained, but the shallow drainage well has poor drainage effect, and the system only has the pressure reduction-drainage well and the upper drainage well to reduce water, so that the integral precipitation speed of the foundation pit is influenced.
As shown in fig. 1 to 2, the penetrating submerged well fast dewatering device for multi-aquifer-multi-aquifer in the present embodiment includes a shallow drainage well 5 for draining water from a low-permeability aquifer 1, a depressurization-drainage well 4 for draining water from a high-permeability aquifer 2 (preferably, in the present embodiment, the depressurization-drainage well 4 and the shallow drainage well 5 are designed in terms of well number and size according to two aquifer layered dewatering (conventional dewatering mode)), and a penetrating submerged well 6 arranged around the depressurization-drainage well 4, wherein the penetrating submerged well 6 has a drill hole 7 drilled through the low-permeability aquifer 1, the high-permeability aquifer 2 and the middle aquifer 3, and is used for communicating the low-permeability aquifer 1 with the high-permeability aquifer 2 to form water channeling up and down. Preferably, the cross-over wells 6 are uniformly arranged around the depressurizing and dewatering wells 4, and the cross-over wells 6 are positioned as close to the vicinity of the depressurizing and dewatering wells 4 as possible. And 2-3 penetrating submerged wells 6 are further preferably arranged around the depressurization-drainage well 4.
In order to ensure that the hydraulic connection is maintained between the low-permeability aquifer 1 and the high-permeability aquifer 2, backfill sand 8 is arranged in the drill hole 7 near the depth of the water isolation layer 3, and a backfill clay 10 is arranged at the upper part of the drill hole 7 to seal the hole. Prevent the low-permeability soil mass in the low-permeability aquifer 1 from blocking the water seepage channel and ensure the high permeability at the lower part of the drill hole 7. The drill hole 7 is used as a cross-layer submerged well 6, and filter pipes are not required to be arranged in the drill hole 7 for drainage, so that the construction cost is greatly reduced. A hole 9 is arranged near the depth of the interface (the water-resisting layer 3) of the two aquifers. The depth vicinity of the water barrier layer 3 is a depth range including the entire water barrier layer 3 and the water-containing layers on the upper and lower sides of the water barrier layer 3.
The method for quickly dewatering the penetrating submerged well of a multi-aquifer-multi-water-barrier adopts the quick dewatering device, and comprises the following steps:
determining that the stratum distribution accords with a multi-aquifer-multi-waterproof layer system 11 and a low-permeability aquifer 1, a waterproof layer 3 and a high-permeability aquifer 2 exist in sequence from top to bottom in a soil layer partitioned by a waterproof curtain 12 (determining that the stratum distribution accords with the applicable condition of the method); determining the problem of slow precipitation rate of a low-permeability aquifer 1 on the upper layer of the project site; in the drilling process of the depressurization-drainage well 1, a cross-layer submerged well 6 is respectively arranged near each depressurization-drainage well 4 to form water channeling up and down; in the construction process of the cross-layer submerged well 6, when the hole is drilled to the depth near the depth of the water-resisting layer 3 (interface of two water-bearing layers), hole expansion is carried out, and after the hole is drilled, sand is timely backfilled and clay is backfilled to seal the hole, so that hole collapse is prevented; in the precipitation process, water is rapidly pumped along with the high-permeability water-bearing stratum 2 of the lower layer to form a water head difference, water in the low-permeability water-bearing stratum 1 of the upper layer is supplied to the high-permeability water-bearing stratum 2 of the lower layer through the drill hole 7 (water near the stratum flows through the cross-layer submerged well to supply the lower layer), and the drainage process is accelerated.
The embodiments described above are intended to facilitate the understanding and use of the invention by those skilled in the art. It will be readily apparent to those skilled in the art that various modifications to these embodiments may be made, and the generic principles described herein may be applied to other embodiments without the use of the inventive faculty. Therefore, the present invention is not limited to the above embodiments, and those skilled in the art should make improvements and modifications within the scope of the present invention based on the disclosure of the present invention.
Claims (7)
1. A method for quickly dewatering a multi-aquifer-multi-water-barrier penetrating submerged well is characterized in that a multi-aquifer-multi-water-barrier penetrating submerged well quick dewatering device is adopted, and in a multi-aquifer-multi-water-barrier system (11), a low-permeability aquifer (1), a water-barrier (3) and a high-permeability aquifer (2) sequentially exist in a soil layer partitioned by a waterproof curtain (12) from top to bottom; the rapid precipitation device comprises a shallow layer drainage well (5) for draining a low-permeability aquifer (1), a depressurization-drainage well (4) for draining a high-permeability aquifer (2) and a through-layer submerged well (6) arranged around the depressurization-drainage well (4), wherein the through-layer submerged well (6) is provided with a drill hole (7) for drilling through the low-permeability aquifer (1), the high-permeability aquifer (2) and a middle water barrier (3) and is used for communicating the low-permeability aquifer (1) with the high-permeability aquifer (2) to form up-and-down water channeling;
the method for quickly dewatering the cross-layer submerged well comprises the following steps:
determining that a low-permeability aquifer (1), a water-resisting layer (3) and a high-permeability aquifer (2) sequentially exist in a soil layer, the stratum distribution of which accords with a multi-aquifer-multi-water-resisting layer system (11) and is separated by a water-stopping curtain (12), and determining that the precipitation rate of the low-permeability aquifer (1) on which engineering site precipitation exists is low;
in the drilling process of the depressurization-drainage wells (4), a layer-crossing submerged well (6) is respectively arranged near each depressurization-drainage well (4) to form up-down water channeling;
in the construction process of the cross-layer submerged well (6), when the hole is drilled to the depth close to the depth of the water-resisting layer (3), hole expansion is carried out, and after the hole is drilled, sand backfill and clay backfill are timely carried out to seal the hole, so that hole collapse is prevented;
in the precipitation process, water is quickly pumped along with the high-permeability water-bearing layer (2) of the lower layer to form a water head difference, and water in the low-permeability water-bearing layer (1) of the upper layer is supplied to the high-permeability water-bearing layer (2) of the lower layer through the drilling holes (7), so that the water drainage process is accelerated.
2. The method for rapidly lowering the water level of the penetrating submarine well for the multi-aquifer-multi-water-barrier according to claim 1, wherein backfill sand (8) is arranged in the drill hole (7) near the depth of the water-barrier (3), and a backfill clay (10) is arranged at the upper part of the drill hole (7) for sealing.
3. The method for the rapid precipitation of a penetrating submersible well for multiple aquifers-multiple aquifers according to claim 1, characterized in that the borehole (7) is provided with a counterbore (9) near the depth of the aquifer (3).
4. The method for rapidly lowering the water level of the penetrating submarine well for the multi-aquifer-multi-water-barrier according to claim 1, wherein the depth vicinity of the water-barrier (3) is a depth range including the whole water-barrier (3) and the aquifers on the upper side and the lower side of the water-barrier (3).
5. The method for the rapid precipitation of a multilaminate-multibarrier multilaminate submersible well according to claim 1, characterized in that the multilaminate submersible well (6) is evenly arranged around the depressurization-drywell (4).
6. The method for rapidly lowering the water level of the multilateral submersible well for the multi-aquifer-multi-water-barrier according to claim 5, characterized in that 2-3 multilateral submersible wells (6) are arranged around the depressurization-drainage well (4).
7. The method for the rapid precipitation of a multilateral submersible well for a multi-aquifer-multi-barrier according to claim 1, characterized in that the borehole (7) of the multilateral submersible well (6) is not provided with a filter pipe.
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| CN2020102474262 | 2020-03-31 | ||
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| JPH09158196A (en) * | 1995-12-05 | 1997-06-17 | Kajima Corp | Drain and soil discharge method in pneumatic caisson method |
| CN101092818A (en) * | 2007-06-07 | 2007-12-26 | 上海交通大学 | Method for lowering water by combining phreatic water in footing groove with artesian aquifer - well stratifications |
| CN103741671A (en) * | 2014-01-22 | 2014-04-23 | 上海长凯岩土工程有限公司 | Groundwater recharge system structure for foundation pit dewatering |
| CN106193076A (en) * | 2016-08-10 | 2016-12-07 | 上海广联环境岩土工程股份有限公司 | Deep basal pit is combined the Groundwater Control method of water-bearing structure |
| CN106337426A (en) * | 2016-09-22 | 2017-01-18 | 苏州市轨道交通集团有限公司 | Dewatering method used for improving surging-resisting stability of confined water stratum foundation pit |
| CN108222082A (en) * | 2018-01-09 | 2018-06-29 | 中南大学 | Foundation pit dynamic precipitation indoor model test method and device under the conditions of multi-aquifer |
-
2020
- 2020-06-18 CN CN202010561996.9A patent/CN111827326B/en active Active
Patent Citations (6)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| JPH09158196A (en) * | 1995-12-05 | 1997-06-17 | Kajima Corp | Drain and soil discharge method in pneumatic caisson method |
| CN101092818A (en) * | 2007-06-07 | 2007-12-26 | 上海交通大学 | Method for lowering water by combining phreatic water in footing groove with artesian aquifer - well stratifications |
| CN103741671A (en) * | 2014-01-22 | 2014-04-23 | 上海长凯岩土工程有限公司 | Groundwater recharge system structure for foundation pit dewatering |
| CN106193076A (en) * | 2016-08-10 | 2016-12-07 | 上海广联环境岩土工程股份有限公司 | Deep basal pit is combined the Groundwater Control method of water-bearing structure |
| CN106337426A (en) * | 2016-09-22 | 2017-01-18 | 苏州市轨道交通集团有限公司 | Dewatering method used for improving surging-resisting stability of confined water stratum foundation pit |
| CN108222082A (en) * | 2018-01-09 | 2018-06-29 | 中南大学 | Foundation pit dynamic precipitation indoor model test method and device under the conditions of multi-aquifer |
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