CN114541494A - Method for monitoring deformation of pile body of cantilever fender pile of deep foundation pit - Google Patents
Method for monitoring deformation of pile body of cantilever fender pile of deep foundation pit Download PDFInfo
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- CN114541494A CN114541494A CN202210196975.0A CN202210196975A CN114541494A CN 114541494 A CN114541494 A CN 114541494A CN 202210196975 A CN202210196975 A CN 202210196975A CN 114541494 A CN114541494 A CN 114541494A
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- E—FIXED CONSTRUCTIONS
- E02—HYDRAULIC ENGINEERING; FOUNDATIONS; SOIL SHIFTING
- E02D—FOUNDATIONS; EXCAVATIONS; EMBANKMENTS; UNDERGROUND OR UNDERWATER STRUCTURES
- E02D33/00—Testing foundations or foundation structures
Abstract
The invention discloses a method for monitoring deformation of a pile body of a cantilever fender pile of a deep foundation pit, which comprises the following steps: firstly, according to the design scheme, excavating a first section of station foundation pit, measuring and lofting exposed fender piles, determining reinforced concrete piles intercepted by a tunnel, identifying, respectively installing a plurality of positioning devices vertically arranged on each reinforced concrete pile, regularly measuring the coordinates of each positioning device by adopting a total station, transmitting the coordinates of each positioning device obtained in the third step to a computer system, judging the displacement condition of each reinforced concrete pile according to the variable quantity of the coordinate values, continuously excavating the station foundation pit in a downward subsection manner, and monitoring the displacement condition of each reinforced concrete pile according to the methods of the second step to the fourth step in each stage until the station construction is finished. The method is simple to operate, economical and reliable, can find whether the foundation pit fender post is in a dangerous condition or not in time, judges the safety and stability of the foundation pit, and ensures the construction safety.
Description
Technical Field
The invention relates to the technical field of construction monitoring and measurement, in particular to a method for monitoring deformation of a pile body of a cantilever fender pile of a deep foundation pit.
Background
At present, the enclosure construction of the subway station mainly comprises a bored pile enclosure structure, a diaphragm wall enclosure structure, direct slope-laying excavation and the like. For the bored pile enclosure structure, the procedures of firstly constructing the bored pile and the inner support structure, then constructing a station and finally constructing a tunnel interval are generally adopted. In order to ensure the whole construction safety, the pile body inclinometer pipe needs to be pre-embedded in advance when the fender pile is constructed, and the displacement condition of the pile body is monitored when a station is constructed. However, in some cases, the construction sequence may be changed, for example, the fender post is constructed first, then the tunnel section is constructed, and finally the station is constructed. According to the construction mode, the fender post b in the excavation area of the tunnel a can be cut off (see fig. 1 and 2), so that the previously pre-embedded pile body inclinometer pipe is damaged, and the deep horizontal displacement condition of the pile body in the foundation pit cannot be monitored in a conventional mode. In addition, the intercepted fender post is divided into an upper section and a lower section by the tunnel, the middle part is suspended, the displacement phenomenon is easier to occur, when the displacement condition of the cantilever post cannot be known accurately in time, the stability of the foundation pit cannot be accurately reflected, early warning cannot be made on the safety of the foundation pit in advance, and the foundation pit of a station has huge potential safety hazards.
Disclosure of Invention
In order to solve the problems, the invention provides a simple, easy, accurate and reliable monitoring method for the deformation of a deep foundation pit cantilever fender pile body, which can specifically adopt the following technical scheme:
the invention relates to a method for monitoring deformation of a pile body of a cantilever fender post of a deep foundation pit, which is suitable for station construction after tunnel excavation and comprises the following steps:
firstly, excavating a first section of station foundation pit according to a design scheme;
secondly, measuring and lofting the exposed fender post, determining a reinforced concrete pile cut off by the tunnel, and marking;
thirdly, respectively installing a plurality of positioning devices vertically arranged on each reinforced concrete pile, and regularly measuring the coordinates of each positioning device by adopting a total station;
fourthly, transmitting the coordinates of the positioning devices obtained in the third step to a computer system, and judging the displacement condition of the reinforced concrete pile according to the variable quantity of the coordinate values;
and fifthly, continuously excavating the foundation pit of the station in a downward segmented manner, and monitoring the displacement condition of the reinforced concrete pile at each stage according to the method from the second step to the fourth step until the construction of the station is finished.
The positioning device comprises
The support is provided with an embedded section positioned in the reinforced concrete pile and a connecting section extending to the outer side of the reinforced concrete pile, and the embedded section is provided with an anti-drop ring;
the mounting plate is arranged on the connecting section and is provided with a mounting surface vertical to the radius of the reinforced concrete pile, and the mounting surface faces away from the reinforced concrete pile;
and the reflector plate is arranged on the mounting surface of the mounting plate and is used for being matched with the total station.
And in the third step, firstly, drilling holes in the reinforced concrete piles, and after slag is removed in the holes, installing the supports of the positioning devices in the holes by adopting a bar planting mode to complete the installation of the positioning devices.
The positioning equipment is vertically arranged in a row on each reinforced concrete pile according to the interval of 0.5 m/and each positioning equipment is at least 1m away from the pile top of the reinforced concrete pile.
In the third step, the coordinates of each positioning device are measured according to the following steps:
s1, setting a coordinate system, selecting a point A and a point B, wherein the coordinate of the point A is (X)A，YA) The azimuth angle of the straight line AB is alphaA-B；
S2, placing the total station at the point B, and measuring the distance D between the total station and the point P where the positioning device is located and the included angle beta between the straight line AB and the straight line AP;
s3, according to formula XP=XA+D*cos（αA-B+ beta) calculating the coordinates (X) of the point P where the positioning device is locatedP，YP）。
YP=XA+D*sin（αA-B+β）
And in the fourth step, judging the displacement condition of the reinforced concrete pile by comparing the variable quantities of the coordinates of the same positioning device at different moments.
The monitoring method for the pile body deformation of the cantilever fender pile of the deep foundation pit is simple to operate, economical and reliable, the positioning device is installed on the cantilever pile containing the embedded steel bars and matched with the on-site total station, the coordinates of the cantilever pile can be rapidly and accurately measured, the displacement data of the cantilever pile is further obtained, whether the foundation pit fender pile is in a dangerous condition or not is found in time, and therefore the safety and the stability of the foundation pit are judged, reasonable measures are taken for remediation, the problems of foundation pit collapse or surrounding pavement uplift and the like are prevented, and construction safety is guaranteed.
Drawings
Fig. 1 is a positional relationship diagram of a foundation pit, a tunnel and a fender post.
Fig. 2 is a sectional view a-a of fig. 1.
Fig. 3 is a schematic view of the installation position of the positioning device of the present invention.
Fig. 4 is a schematic diagram of a coordinate measuring device according to the present invention.
Fig. 5 is a schematic diagram of coordinate system setting for coordinate measurement in the embodiment.
Detailed Description
The following describes embodiments of the present invention in detail with reference to the accompanying drawings, which are implemented on the premise of the technical solution of the present invention, and give detailed implementation manners and specific construction processes, but the scope of the present invention is not limited to the following embodiments.
As shown in fig. 3 and 4, the method for monitoring the deformation of the pile body of the cantilever fender post of the deep foundation pit is suitable for the construction of a station after a tunnel is excavated, and comprises the following steps:
firstly, excavating a first section of station foundation pit according to a design scheme;
secondly, measuring and lofting the exposed fender post, determining a reinforced concrete pile 1 (namely the fender post with the built-in steel bars) cut off by the tunnel, and identifying;
thirdly, a plurality of positioning devices 2 which are vertically arranged are respectively arranged on each reinforced concrete pile 1, and the coordinates of each positioning device 2 are measured at regular time by adopting a total station 3;
the positioning device 2 consists of a support 21, a mounting plate 22 and a reflector plate 23, wherein the support 21 is an L-shaped structure made of a steel bar with the diameter phi of 14, and is provided with a buried section positioned in the reinforced concrete pile 1 and a connecting section extending to the outer side of the reinforced concrete pile 1, and the buried section is provided with an anti-falling ring 24; the mounting plate 22 is a galvanized steel plate with the length of 6 multiplied by 6cm, is welded on the connecting section of the bracket 21, and is provided with a mounting surface vertical to the radius of the reinforced concrete pile 1, and the mounting surface faces back to the reinforced concrete pile 1; a reflector plate 25 is mounted on the mounting surface for use with the total station 3.
When the positioning device 2 is installed, firstly, a drill bit with the diameter of phi 14 is adopted to drill a hole on the reinforced concrete pile 1, after the designed hole depth is reached, a blower is used for removing slag in the hole, and then the support 21 with the reflector plate 25 is installed in the hole in a bar planting mode. The mounting holes of the support 21 are vertically arranged in a row on each reinforced concrete pile 1 according to the interval of 0.5 m/and the distance between the topmost mounting hole and the pile top of the reinforced concrete pile 1 is at least 1 m.
Above-mentioned positioner simple structure, easily preparation, it cooperatees with total powerstation 3 and can conveniently record the coordinate of each positioner 2, specifically as follows:
s1, setting a coordinate system, selecting a point A and a point B, wherein the coordinate of the point A is (X)A，YA) The azimuth angle of the straight line AB is alphaA-B；
S2, placing the total station at the point B, and measuring the distance D between the total station and the point P where the positioning device is located and the included angle beta between the straight line AB and the straight line AP;
s3, according to the formula XP=XA+D*cos（αA-B+ beta) calculating the coordinates (X) of the point P where the positioning device is locatedP，YP）。
YP=XA+D*sin（αA-B+β）
In order to ensure the measurement accuracy, the coordinates of each positioning device 2 are measured 2-4 times according to the above method, the average value of β and D is taken, and the coordinates of the point P are calculated according to the formula described in S3.
The coordinates of each positioning device 2 are typically calculated once at 24 hour intervals.
And fourthly, transmitting the coordinates of the positioning devices 2 obtained in the third step to a computer system, and comparing the variable quantity of the coordinate values to judge the displacement condition of the reinforced concrete pile 1. In general, the displacement of the reinforced concrete pile 1 is often determined based on the amount of change in the coordinates of the same positioning device 2 at different times.
As shown in fig. 5, the center of the overlapping area of the rectangular foundation pit K and the tunnel a is used as a coordinate system origin o, the central axis (east-west direction) of the tunnel a is used as an X-axis, the perpendicular line (north-south direction) of the central axis is used as a y-axis, and the coordinate of the point P measured on the first day is (X)1，Y1) The point P measured the next day has the coordinate of (X)2，Y2) When (X)2-X1) When the difference value is a positive value, the reinforced concrete pile 1 has an east movement trend, and on the contrary, when the difference value is a negative value, the reinforced concrete pile 1 has a west movement trend; in the same way, when (Y)2-Y1) When the difference value of (a) is a positive value, the reinforced concrete pile 1 has a north movement trend, and conversely, when the difference value of (b) is a negative value, the reinforced concrete pile 1 has a south movement trend. In addition, can also be obtained by
The amount of displacement is calculated.
And fifthly, continuously excavating the foundation pit of the station in a downward segmented manner, and monitoring the displacement condition of the reinforced concrete pile at each stage according to the method from the second step to the fourth step until the construction of the station is finished.
It should be noted that in the description of the present invention, terms such as "front", "rear", "left", "right", "vertical", "horizontal", "inner", "outer", and the like indicate orientations or positional relationships based on the orientations or positional relationships shown in the drawings, and are only for convenience of description and simplification of description, but do not indicate or imply that the device or element referred to must have a specific orientation, be constructed and operated in a specific orientation, and thus, should not be construed as limiting the present invention.
Claims (6)
1. A monitoring method for deformation of a pile body of a cantilever fender pile of a deep foundation pit is suitable for station construction after a tunnel is excavated, and is characterized by comprising the following steps:
firstly, excavating a first section of station foundation pit according to a design scheme;
secondly, measuring and lofting the exposed fender post, determining a reinforced concrete pile cut off by the tunnel, and marking;
thirdly, respectively installing a plurality of positioning devices vertically arranged on each reinforced concrete pile, and adopting a total station to measure the coordinates of each positioning device at regular time;
fourthly, transmitting the coordinates of the positioning devices obtained in the third step to a computer system, and judging the displacement condition of the reinforced concrete pile according to the variable quantity of the coordinate values;
and fifthly, continuously excavating the foundation pit of the station in a downward segmented manner, and monitoring the displacement condition of the reinforced concrete pile at each stage according to the method from the second step to the fourth step until the construction of the station is finished.
2. The monitoring method for the deformation of the pile body of the cantilever fender pile of the deep foundation pit as claimed in claim 1, is characterized in that: the positioning device comprises
The support is provided with a buried section located in the reinforced concrete pile and a connecting section extending to the outer side of the reinforced concrete pile, and the buried section is provided with an anti-falling ring;
the mounting plate is arranged on the connecting section and is provided with a mounting surface vertical to the radius of the reinforced concrete pile, and the mounting surface faces away from the reinforced concrete pile;
and the reflector plate is arranged on the mounting surface of the mounting plate and is used for being matched with the total station.
3. The monitoring method for the deformation of the pile body of the cantilever fender pile of the deep foundation pit as claimed in claim 2, is characterized in that: and in the third step, firstly, drilling holes in the reinforced concrete piles, and after slag is removed in the holes, installing the supports of the positioning devices in the holes by adopting a bar planting mode to complete the installation of the positioning devices.
4. The monitoring method for the deformation of the pile body of the cantilever fender pile of the deep foundation pit as claimed in claim 1, is characterized in that: the positioning equipment is vertically arranged in a row on each reinforced concrete pile according to the interval of 0.5 m/and each positioning equipment is at least 1m away from the pile top of the reinforced concrete pile.
5. The monitoring method for the deformation of the pile body of the cantilever fender pile of the deep foundation pit as claimed in claim 1, is characterized in that: in the third step, the coordinates of each positioning device are measured according to the following steps:
s1, setting a coordinate system, selecting a point A and a point B, wherein the coordinate of the point A is (X)A，YA) The azimuth angle of the straight line AB is alphaA-B；
S2, placing the total station at the point B, and measuring the distance D between the total station and the point P where the positioning device is located and the included angle beta between the straight line AB and the straight line AP;
s3, according to formula XP=XA+D*cos（αA-B+ beta) calculating the coordinates (X) of the point P where the positioning device is locatedP，YP）；
YP=XA+D*sin（αA-B+β）。
6. The monitoring method for the deformation of the pile body of the cantilever fender pile of the deep foundation pit as claimed in claim 1, is characterized in that: and in the fourth step, judging the displacement condition of the reinforced concrete pile by comparing the variable quantities of the coordinates of the same positioning device at different moments.
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| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| CN202210196975.0A CN114541494A (en) | 2022-03-02 | 2022-03-02 | Method for monitoring deformation of pile body of cantilever fender pile of deep foundation pit |
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| Application Number | Priority Date | Filing Date | Title |
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| CN202210196975.0A CN114541494A (en) | 2022-03-02 | 2022-03-02 | Method for monitoring deformation of pile body of cantilever fender pile of deep foundation pit |
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| CN114541494A true CN114541494A (en) | 2022-05-27 |
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| CN202210196975.0A Pending CN114541494A (en) | 2022-03-02 | 2022-03-02 | Method for monitoring deformation of pile body of cantilever fender pile of deep foundation pit |
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| CN102589533A (en) * | 2012-01-19 | 2012-07-18 | 西安科技大学 | Method for measuring hidden point position coordinates by utilizing total-station instrument |
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| CN109115149A (en) * | 2018-08-13 | 2019-01-01 | 山东大学 | A kind of soil mass of foundation pit side slope deeply mixing cement-soil pile monitoring method based on measurement of coordinates |
| CN210685982U (en) * | 2019-08-22 | 2020-06-05 | 中铁十二局集团第二工程有限公司 | Automatic monitoring system for deformation of subway crossing building |
| CN111764447A (en) * | 2020-07-20 | 2020-10-13 | 天津市地质工程勘察院 | Method for monitoring horizontal displacement of pile top of foundation pit supporting pile |
-
2022
- 2022-03-02 CN CN202210196975.0A patent/CN114541494A/en active Pending
Patent Citations (8)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| JP2005024492A (en) * | 2003-07-02 | 2005-01-27 | Taisei Corp | Measuring method for displacement of inside shape of tunnel |
| CN102409703A (en) * | 2011-08-17 | 2012-04-11 | 北京交通大学 | Monitoring method for horizontal displacement of foundation pit pile top and monitoring device thereof |
| CN102589533A (en) * | 2012-01-19 | 2012-07-18 | 西安科技大学 | Method for measuring hidden point position coordinates by utilizing total-station instrument |
| CN203420265U (en) * | 2013-07-30 | 2014-02-05 | 上海城建市政工程（集团）有限公司 | System for monitoring deformation of edge of foundation ditch |
| CN103884319A (en) * | 2014-03-13 | 2014-06-25 | 内蒙古电力勘测设计院 | Total station-free tower footing cross-section diagram measuring method and equipment |
| CN109115149A (en) * | 2018-08-13 | 2019-01-01 | 山东大学 | A kind of soil mass of foundation pit side slope deeply mixing cement-soil pile monitoring method based on measurement of coordinates |
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