CN112878322B - Construction method of anchor rod below groundwater level - Google Patents
Construction method of anchor rod below groundwater level Download PDFInfo
- Publication number
- CN112878322B CN112878322B CN202110308339.8A CN202110308339A CN112878322B CN 112878322 B CN112878322 B CN 112878322B CN 202110308339 A CN202110308339 A CN 202110308339A CN 112878322 B CN112878322 B CN 112878322B
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- grouting
- anchor rod
- pipe
- slurry
- cement
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Classifications
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- E—FIXED CONSTRUCTIONS
- E02—HYDRAULIC ENGINEERING; FOUNDATIONS; SOIL SHIFTING
- E02D—FOUNDATIONS; EXCAVATIONS; EMBANKMENTS; UNDERGROUND OR UNDERWATER STRUCTURES
- E02D5/00—Bulkheads, piles, or other structural elements specially adapted to foundation engineering
- E02D5/74—Means for anchoring structural elements or bulkheads
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- E—FIXED CONSTRUCTIONS
- E02—HYDRAULIC ENGINEERING; FOUNDATIONS; SOIL SHIFTING
- E02D—FOUNDATIONS; EXCAVATIONS; EMBANKMENTS; UNDERGROUND OR UNDERWATER STRUCTURES
- E02D15/00—Handling building or like materials for hydraulic engineering or foundations
- E02D15/02—Handling of bulk concrete specially for foundation or hydraulic engineering purposes
- E02D15/04—Placing concrete in mould-pipes, pile tubes, bore-holes or narrow shafts
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- E—FIXED CONSTRUCTIONS
- E02—HYDRAULIC ENGINEERING; FOUNDATIONS; SOIL SHIFTING
- E02D—FOUNDATIONS; EXCAVATIONS; EMBANKMENTS; UNDERGROUND OR UNDERWATER STRUCTURES
- E02D17/00—Excavations; Bordering of excavations; Making embankments
- E02D17/02—Foundation pits
- E02D17/04—Bordering surfacing or stiffening the sides of foundation pits
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- E—FIXED CONSTRUCTIONS
- E02—HYDRAULIC ENGINEERING; FOUNDATIONS; SOIL SHIFTING
- E02D—FOUNDATIONS; EXCAVATIONS; EMBANKMENTS; UNDERGROUND OR UNDERWATER STRUCTURES
- E02D2250/00—Production methods
- E02D2250/0023—Cast, i.e. in situ or in a mold or other formwork
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- E—FIXED CONSTRUCTIONS
- E02—HYDRAULIC ENGINEERING; FOUNDATIONS; SOIL SHIFTING
- E02D—FOUNDATIONS; EXCAVATIONS; EMBANKMENTS; UNDERGROUND OR UNDERWATER STRUCTURES
- E02D2300/00—Materials
- E02D2300/0004—Synthetics
- E02D2300/0018—Cement used as binder
Abstract
The invention provides a construction method of an anchor rod below the groundwater level, which comprises the following construction steps: drilling holes on the soil between the support piles by adopting an anchor rod drilling machine; plugging the drilled holes by cotton threads; inserting the anchor cable from the orifice to the bottom of the hole and grouting; a secondary pressure grouting pipe is additionally arranged in the hole for secondary pressure grouting, and a drainage pipe is arranged at the orifice; adding a tertiary hole bottom split grouting pipe for carrying out tertiary split grouting; stretching after the slurry reaches a preset strength, setting four-time pressure grouting pipes after stretching, and performing four-time pressure grouting; and observing whether the underground water oozes out from the orifice after four grouting processes are completed. According to the scheme, the four grouting methods are adopted for the anchor rod construction method below the groundwater level, so that the quality of the anchor rod is ensured, cement paste is prevented from flowing outwards, and the groundwater can be effectively prevented from flowing out of the orifice after tensioning is finished, so that no water leakage at the open end of the anchor rod is ensured, and the difficulty of water stopping of the anchor rod opening below the groundwater level is reduced.
Description
Technical Field
The invention relates to the technical field of anchor rod construction, in particular to an anchor rod construction method below the groundwater level.
Background
At present, pile anchor support is a main support form in a foundation pit support structure. Before the anchor rod construction, pile body structures around the foundation pit are completed, and the anchor rod mainly plays a role in tie-down of the pile body. The general anchor rod construction is mainly to drill holes in the soil layer behind the support piles by an anchor rod drilling machine; after drilling to the designed depth, inserting the anchor cable from the orifice to the bottom of the hole, grouting, and withdrawing the drill rod while grouting; stopping grouting until the cement paste emerges from the hole; then carrying out secondary grouting; and tensioning the anchor rod after the cement slurry in the hole reaches the requirement of the tensile strength.
From the current construction technology, the anchor rod open pore grouting technology below the water level is applied less, and the anchor rod drilling opening is generally positioned above the water level so as to ensure no water leakage of the drilling point. Because the depth of the foundation pit is increased along with the development of technology at present, when the underground water level is higher or after construction in rainy season, whether the anchor rod opening is positioned above the water level cannot be guaranteed. And the anchor rod has water to gush out from the trompil position under groundwater water level trompil, appears gushing sand phenomenon even, seriously influences the stability of foundation ditch.
Disclosure of Invention
The invention aims to solve the technical problem of providing a construction method of an anchor rod below the groundwater level so as to solve the problem that water gushes out from an opening position when the anchor rod is opened below the groundwater level, even sand gushing occurs, and stability of a foundation pit is seriously affected.
In order to solve the technical problems, the invention provides the following technical scheme:
the construction method of the anchor rod below the groundwater level comprises the following construction steps:
step 1: drilling holes on a soil body or a waterproof curtain cement slurry system between the support piles by adopting an anchor rod drilling machine;
step 2: plugging the drilled holes by cotton threads;
step 3: inserting the anchor cable from the orifice to the bottom of the hole and grouting;
step 4: a secondary pressure grouting pipe is additionally arranged in the hole for secondary pressure grouting, and a drainage pipe is arranged at the orifice;
step 5: adding a tertiary hole bottom split grouting pipe in the rod body of the anchor rod, and performing tertiary split grouting;
step 6: stretching after the slurry reaches a preset strength, setting four-time pressure grouting pipes in the holes after stretching, and performing four-time pressure grouting;
step 7: and (3) observing whether the underground water oozes out of the orifice after the four-time pressure grouting is finished, and if so, continuing to repeat the step (6) until the orifice does not ooze out of water.
The upper part of the secondary pressure grouting pipe adopts an iron pipe, the lower part adopts a plastic grouting pipe, and a plurality of grouting holes are formed in the bottom of the plastic grouting pipe.
Wherein, the secondary pressure grouting adopts cement-water glass double-liquid grouting.
The three-hole bottom split grouting pipe is 0.4 m-0.6 m longer than the length of the anchor rod, the upper part of the three-hole bottom split grouting pipe adopts an iron pipe, the lower part adopts a plastic grouting pipe, and a plurality of grouting holes are formed in the bottom of the plastic grouting pipe.
In the three-time splitting grouting, the cement per linear meter is not less than 80kg, and the grouting pressure is 2-4 MPa.
Wherein, the grouting of the three-time splitting grouting is doped with a water reducing agent.
The end part of the four-time pressure grouting pipe extending out of the anchor rod is sealed by a plug, and a plurality of grout outlet holes are formed in the end part of the four-time pressure grouting pipe extending into the anchor rod.
Wherein, the four-time pressure grouting adopts cement-water glass double-liquid grouting.
The technical scheme of the invention has the following beneficial effects:
in the scheme, the construction method of the anchor rod below the groundwater level ensures the quality of the anchor rod and simultaneously ensures that cement paste does not outflow through four grouting, and can also effectively prevent groundwater from flowing out of the orifice after tensioning is finished, thereby ensuring no water leakage at the open end of the anchor rod and reducing the difficulty of water stopping of the anchor rod opening below the groundwater level.
Drawings
FIG. 1 is a schematic side view of the method of the present invention for constructing an anchor below the groundwater level;
FIG. 2 is a schematic front view of the method of the present invention for constructing an anchor below the groundwater level;
FIG. 3 is a schematic view of a secondary pressure grouting pipe according to the invention;
FIG. 4 is a schematic view of a tertiary hole bottom split grouting pipe of the present invention;
fig. 5 is a schematic view of a four-time pressure grouting pipe according to the invention.
[ reference numerals ]
1. Soil mass;
2. supporting piles;
3. elevation of underground water level;
4. drilling holes;
5. a bolt;
6. splitting the grouting pipe at the bottom of the tertiary hole;
7. four times of pressure grouting pipes;
8. and (5) a secondary pressure grouting pipe.
Detailed Description
In order to make the technical problems, technical solutions and advantages to be solved more apparent, the following detailed description will be given with reference to the accompanying drawings and specific embodiments.
As shown in fig. 1 to 5, an embodiment of the present invention provides a method for constructing an anchor below a groundwater level, including the following construction steps:
step 1: drilling holes on the soil body 1 between the support piles 2 by adopting an anchor rod drilling machine, and if the water curtain system is arranged in the middle of the support piles 2, drilling by adopting a special diamond drill bit of a processing plant by adopting a rotary process until the water curtain is penetrated, so that a drilling hole 4 with the diameter matched with the anchor rod 5 is formed, and the rest parts of the water curtain are not damaged;
step 2: the polyurethane cotton yarn is adopted to seal the drilling holes 4 so as to prevent sand from overflowing, and if water flows out during sealing, a drainage catheter can be buried first;
step 3: the anchor cable is inserted into the hole bottom from the hole opening and grouting is carried out, the drill rod is withdrawn while grouting is carried out, and grouting is stopped until cement paste emerges from the hole;
step 4: in order to prevent the flow of groundwater within a 10m range in a hole from affecting the construction quality of an anchor rod, a secondary pressure grouting pipe 8 is additionally arranged within a range extending inwards by 10m from an orifice for secondary pressure grouting, and a drainage pipe is arranged at the orifice;
step 5: a tertiary hole bottom split grouting pipe 6 is additionally arranged in a rod body of the anchor rod 5, and tertiary split grouting is carried out;
step 6: stretching after the slurry reaches a preset strength, and setting a four-time pressure grouting pipe 7 for four-time pressure grouting after stretching to ensure that the orifice part is not leaked;
step 7: and (3) observing whether the underground water oozes out of the orifice after the four-time pressure grouting is finished, and if so, continuing to repeat the step (6) until the orifice does not ooze out of water.
As shown in fig. 1, the position of the drill hole 4 is below the ground water level elevation 3, and before the construction is started, the ground water level elevation in the foundation pit needs to be ensured to be lower than the anchor rod hole elevation, so that the requirement of an anchor rod construction working surface is met.
In this embodiment, the upper portion of the secondary pressure grouting pipe 8 adopts a DN20 iron pipe, the lower portion adopts a plastic grouting pipe detachably connected with the iron pipe, as shown in fig. 3, a plurality of grouting holes with diameters of 6mm are formed in the bottom 2m of the plastic grouting pipe of the secondary pressure grouting pipe 8, and the intervals between the grouting holes are 500mm.
The secondary pressure grouting adopts cement-water glass double-liquid slurry, and the cement-water glass double-liquid slurry has the following advantages: the slurry has low viscosity and good pourability, can be quickly solidified in water, can accurately control the gel time within a few seconds to tens of minutes, has high calculus rate up to more than 98 percent, has high calculus strength, and can effectively control groundwater in holes to flow out from the orifice.
Specifically, the parameters of the cement-water glass double slurry are as follows:
cement paste water cement ratio=0.5:1 (weight ratio);
cement paste: water glass=1:0.5 to 1:1.0 (volume ratio).
In this embodiment, the length of the tertiary hole bottom split grouting pipe 6 is 0.4-0.6 m longer than that of the anchor rod 5, the upper portion of the tertiary hole bottom split grouting pipe 6 adopts a DN20 iron pipe, the lower portion adopts a plastic grouting pipe detachably connected with the iron pipe, as shown in fig. 4, the bottom 2m of the plastic grouting pipe of the tertiary hole bottom split grouting pipe 6 is provided with a plurality of grouting holes with diameters of 6mm, and the interval between the grouting holes is 500mm.
In the three-time splitting grouting, the cement per linear meter is not less than 80kg, and the grouting pressure is 2-4 MPa.
In addition, the grouting water cement ratio of the three-time split grouting is 0.45 (weight ratio), and the grouting of the three-time split grouting is doped with a water reducing agent, wherein the weight ratio of the water reducing agent to cement is 4% -6%.
In this embodiment, the DN20 iron pipe is adopted for the four-time pressure grouting pipe 7, as shown in fig. 5, a plug seal is adopted for 500mm of the end portion of the four-time pressure grouting pipe 7 extending out of the anchor rod 5, a plurality of grout outlet holes with diameters of 6mm are formed in 500mm of the end portion of the four-time pressure grouting pipe extending into the anchor rod 5, and the distance between the grout outlet holes is 100mm.
The four-time pressure grouting adopts cement-water glass double-liquid grouting, and the parameters are as follows:
cement paste water cement ratio=0.5:1 (weight ratio);
cement paste: water glass=1:0.5 to 1:1.0 (volume ratio).
In this scheme, the slurry must be stirred uniformly and the slurry density measured, and if a common stirrer is used, the stirring time of the pure cement slurry should be more than 3min. The slurry should be screened twice before use, the time from pulping to exhaustion should not be longer than 4 hours, and the temperature of the slurry should be kept between 5 and 40 ℃. The grouting equipment adopts a pump special for double-liquid grouting, prepares the slurry according to a specified proportion, controls the gel time to be about 30s, and can properly adjust the proportion of the slurry when the requirement is not met.
In this embodiment, a water drill is used to drill a hole in the soil body 1. In addition, in order to prevent adjacent anchor rod drilling from disturbing each other and affecting the anchor rod construction quality, grouting hole construction and anchor rod construction should be staggered, and the interval is not smaller than 10m when synchronous construction is performed.
In the scheme, the construction method of the anchor rod below the groundwater level ensures the quality of the anchor rod and simultaneously ensures that cement paste does not outflow through four grouting, and can also effectively prevent groundwater from flowing out of the orifice after tensioning is finished, thereby ensuring no water leakage at the open end of the anchor rod and reducing the difficulty of water stopping of the anchor rod opening below the groundwater level.
While the foregoing is directed to the preferred embodiments of the present invention, it will be appreciated by those skilled in the art that various modifications and adaptations can be made without departing from the principles of the present invention, and such modifications and adaptations are intended to be comprehended within the scope of the present invention.
Claims (1)
1. The construction method of the anchor rod below the groundwater level is characterized by comprising the following construction steps:
step 1: drilling holes on a soil body or a waterproof curtain cement slurry system between the support piles by adopting an anchor rod drilling machine, drilling by adopting a diamond drill bit and adopting a rotary process until penetrating through the waterproof curtain to form a drill hole with the diameter matched with the anchor rod, and not damaging other parts of the waterproof curtain;
step 2: plugging the drilled hole by cotton threads, and if water outflow occurs during plugging, firstly burying a drainage catheter;
step 3: the anchor cable is inserted into the hole bottom from the hole opening and grouting is carried out, the drill rod is withdrawn while grouting is carried out, and grouting is stopped until cement paste emerges from the hole;
step 4: adding a secondary pressure grouting pipe in a range extending inwards for 10m in the hole, performing secondary pressure grouting, and arranging a drainage pipe at the hole opening; the upper part of the secondary pressure grouting pipe adopts an iron pipe, the lower part of the secondary pressure grouting pipe adopts a plastic grouting pipe, the iron pipe is detachably connected with the plastic grouting pipe, and the bottom of the plastic grouting pipe is provided with a plurality of grouting holes; the secondary pressure grouting adopts cement-water glass double-liquid grouting; the weight ratio of cement paste to water ash is=0.5:1, and the volume ratio of cement paste to water glass is=1:0.5-1:1.0;
step 5: adding a tertiary hole bottom split grouting pipe in the rod body of the anchor rod, and performing tertiary split grouting; the three-hole bottom split grouting pipe is 0.4 m-0.6 m longer than the length of the anchor rod, the upper part of the three-hole bottom split grouting pipe adopts an iron pipe, the lower part of the three-hole bottom split grouting pipe adopts a plastic grouting pipe, the iron pipe is detachably connected with the plastic grouting pipe, and a plurality of grouting holes are formed in the bottom of the plastic grouting pipe; a plurality of grouting holes with the diameter of 6mm are formed in the position, 2m away from the bottom of the tertiary hole bottom split grouting pipe, of the plastic grouting pipe of the tertiary hole bottom split grouting pipe, and the interval between the grouting holes is 500mm; in the three-time splitting grouting, each linear meter of cement is not less than 80kg, and the grouting pressure is 2-4 MPa; the weight ratio of grouting water to ash of the three-time splitting grouting is 0.45, a water reducing agent is added into the three-time splitting grouting, and the weight ratio of the water reducing agent to cement is 4% -6%;
step 6: stretching after the slurry reaches a preset strength, setting four-time pressure grouting pipes in the holes after stretching, and performing four-time pressure grouting; the end part of the four-time pressure grouting pipe extending out of the anchor rod is sealed by a plug, and a plurality of grout outlets are formed in the end part of the four-time pressure grouting pipe extending into the anchor rod; the four-time pressure grouting adopts cement-water glass double-liquid slurry, the weight ratio of cement paste water ash is=0.5:1, and the volume ratio of cement paste to water glass is=1:0.5-1:1.0;
step 7: observing whether the orifice has groundwater oozes or not after the four-time pressure grouting is finished, if so, continuing to repeat the step 6 until the orifice has no groundwater oozes;
the slurry comprises the cement slurry, the cement-water glass double-liquid slurry of the secondary pressure grouting, the grouting water of the tertiary splitting grouting and the cement-water glass double-liquid slurry of the quaternary pressure grouting, any one of the slurry is required to be uniformly stirred and the slurry density is measured, and if a common stirrer is adopted, the stirring time of the pure cement slurry is required to be longer than 3min; the slurry should be screened twice before use, the time from pulping to exhaustion should not be longer than 4 hours, and the temperature of the slurry should be kept between 5 ℃ and 40 ℃; the grouting equipment adopts a double-liquid grouting pump to prepare the slurry according to a specified proportion, the gel time is controlled to be 30s, and the proportion of the slurry can be properly adjusted when the requirement is not met.
Priority Applications (1)
| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| CN202110308339.8A CN112878322B (en) | 2021-03-23 | 2021-03-23 | Construction method of anchor rod below groundwater level |
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| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| CN202110308339.8A CN112878322B (en) | 2021-03-23 | 2021-03-23 | Construction method of anchor rod below groundwater level |
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| CN112878322A CN112878322A (en) | 2021-06-01 |
| CN112878322B true CN112878322B (en) | 2023-08-01 |
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Family Cites Families (6)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| SE318830B (en) * | 1964-11-11 | 1969-12-15 | Sandvikens Jernverks Ab | |
| CN101570970A (en) * | 2008-04-07 | 2009-11-04 | 李宪奎 | Construction method of cement soil anchor and anchor plate combined member thereof |
| CN103088819B (en) * | 2013-02-22 | 2016-04-06 | 北京市政路桥股份有限公司 | Construction prestressed cable method |
| CN104164874B (en) * | 2013-05-16 | 2017-03-01 | 建研地基基础工程有限责任公司 | The construction method of the anchor cable structure of application swelled ground anchor rope grouting-stop plug |
| CN103924592B (en) * | 2014-04-18 | 2016-08-24 | 周同和 | A kind of pressure-type PHA anchor pole and construction method thereof |
| CN111441392A (en) * | 2020-05-11 | 2020-07-24 | 陕西建工机械施工集团有限公司 | Grouting water guide leakage stoppage structure and underwater jet grouting anchor cable water stop construction method |
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