CN112359806A - Device and method for monitoring influence of deep foundation pit excavation on vertical deformation of subway - Google Patents
Device and method for monitoring influence of deep foundation pit excavation on vertical deformation of subway Download PDFInfo
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Abstract
A device and a method for monitoring the influence of deep foundation pit excavation on subway vertical deformation belong to the technical field of geotechnical engineering and underground space engineering field monitoring, and comprise monitoring rod pieces, observation prisms, anti-tilting concentric supports, protective sleeves, filling sand and concrete bases, wherein the monitoring rod pieces are connected with hollow head ends through threaded ends of the connected rod pieces, the tops of the connected monitoring rod pieces are connected with the observation prisms, the bottoms of the connected monitoring rod pieces are connected with the concrete bases, the protective sleeves are arranged outside the connected monitoring rod pieces, and the filling sand is filled between the monitoring rod pieces and the protective sleeves. According to the method, the vertical displacement of the deep soil body in the pit and the vertical displacement of the subway tunnel in the deep foundation pit excavation process are combined, the safety of the deep foundation pit excavation on subway operation is timely evaluated through dynamic monitoring and early warning, so that the soil layer deformation rules of the subway tunnel, the foundation pit and the periphery of the foundation pit in the deep foundation pit excavation process are obtained, and a decision basis is provided for excavation of the near-subway deep foundation pit.
Description
Technical Field
The invention belongs to the technical field of geotechnical engineering and underground space engineering field monitoring, and particularly relates to a device and a method for monitoring the influence of deep foundation pit excavation on subway vertical deformation.
Background
At present, urban rail transit is developed vigorously nationwide, and the established operation and urban subway traffic plays a great role in promoting the development of regional economy. The construction of the subway mostly passes through a busy city area, so that the construction of residential, commercial, municipal and other projects along the subway is driven, and a unique economic development circle along the subway is formed. The excavation of the deep foundation pit can cause the constructed subway tunnel to generate vertical uplift deformation and lateral deformation, particularly the subway near the deep foundation pit, which brings great threat to the daily safe operation of the subway.
The existing deep foundation pit monitoring focuses on horizontal deformation of the side wall of the deep foundation pit and vertical displacement in a certain range outside the foundation pit due to the requirements of specifications and policies, and focuses on less vertical uplift of soil layers with certain depth inside and outside the pit in the excavation process of the deep foundation pit.
Disclosure of Invention
Based on the technical background, the invention provides a device and a method for monitoring the influence of deep foundation pit excavation on subway vertical deformation.
In order to achieve the purpose, the invention adopts the following technical scheme:
the utility model provides a deep basal pit excavation is to vertical deformation influence monitoring devices of subway, includes monitoring member, observation prism, prevents inclining concentric support, a protective sleeve section of thick bamboo, packing sand, concrete base, the one end of monitoring member is equipped with outside outstanding screw thread end, and the other end is equipped with inside sunken hollow head end, and the screw thread end through continuous member links to each other with hollow head end between the monitoring member, and monitoring member top after the connection links to each other with the observation prism, and its bottom links to each other with concrete base, and the monitoring member outside after the connection is equipped with a protective sleeve section of thick bamboo, the monitoring member supports with a protective sleeve section of thick bamboo through preventing inclining concentric support and links to each other, it has packing sand to fill between monitoring member and the protective sleeve.
Further, the length of the hollow head end is greater than that of the threaded head end.
Furthermore, the upper part of the observation prism is a prism end, the bottom of the observation prism is provided with a threaded connection end, and the observation prism is connected with the hollow head end at the top of the monitoring rod piece through the threaded connection end.
Further, the anti-tilting concentric brackets outside the monitoring rod are arranged one by one at intervals of 0.5-2 m.
A method for monitoring the influence of excavation of a near-subway deep foundation pit on subway vertical deformation is characterized in that a supporting pile is constructed, a monitoring device is installed, each foundation pit is provided with 2-4 monitoring sections, and each section is provided with 3-5 measuring points; corresponding to the position of the foundation pit in the subway tunnelMonitoring points are arranged at the junction of the extension line of the corresponding monitoring section and the tunnel in the extension range, at least one measuring point is arranged outside the extension range of the plane position of the foundation pit, the horizontal distance of each monitoring point is 10-30 m, and the monitoring points are arranged at one side of the tunnel in a deviation manner; at least 3 datum points and 1 working base point are respectively arranged above the ground and in the tunnel, an observation point outside a foundation pit on the ground is directly observed by the datum point, an observation working base point is established at the side of the foundation pit by a measuring point in the foundation pit, a triangle elevation measuring instrument is adopted to monitor the elevation change of the measuring point in the pit, and the elevation change of each measuring point in the tunnel is based on the elevation change of each measuring point measured by the datum point far away from the foundation pit in the tunnel; before excavation of foundation pit, initial value H of elevation of each measuring point ground measuring rod piece observation prismij1Wherein: i is a measuring point number; j: numbering the rod pieces at the measuring points; 1, a first-time elevation value of a j rod piece of the i measuring point and an initial elevation value of each measuring point outside a foundation pit and inside a tunnel; monitoring the elevation change of each measuring point according to a certain frequency in the excavation process of each layer of soil body; when the excavation of each layer of soil is finished, before the next layer of soil is excavated, the elevation of the prism of the soil monitoring rod piece of the layer is collected, the monitoring device at the section is dismounted after the collection is finished, the prism is mounted on the next-stage rod piece, and the elevation is collected to be used as the initial value of the elevation before the next layer of soil is excavated; excavating each layer of soil, collecting an initial elevation value, a plurality of process elevation values and a last elevation value, and calculating the sum (L) of the effective length of a rod piece and the size of a prism according to the elevation difference between the last elevation value of the previous layer of soil and the initial elevation value of the next layer of soili+ a 3); and obtaining the accumulated deformation value delta Hi of each measuring point, the ratio of the accumulated deformation value, namely the deformation rate, to the accumulated days, and the ratio of the stage deformation value delta Hij to the deformation rate, namely the stage deformation value, to the stage days through the data.
Furthermore, the datum point above the ground is a stable and reliable elevation control point which is not less than 2 times of the pit depth from the empty surface of the foundation pit and is not easily influenced by the external environment.
Further, the method for installing the monitoring device comprises the steps of drilling a hole at a target measuring point to a depth 1-2m below the depth of a designed foundation pit before excavation, placing a protective sleeve, pouring a small amount of concrete mortar into the sleeve to form a base, inserting the assembled rod piece into the base before initial setting, and ensuring that the rod piece and the sleeve are concentric by adopting a concentric anti-tilting support in the inserting process; filling quantitative filling sand such as silty sand and the like into the sleeve uniformly, arranging an anti-tilting concentric support at intervals of 0.5-2m until the filling sand is filled at the port above the ground of the protective sleeve, screwing the observation prism into a port threaded hole, arranging a striking small red flag next to a monitoring point so as to disturb the measuring point in the excavation process, and removing a section of protective sleeve and a section of monitoring rod piece when excavating a layer of soil along with the excavation.
Furthermore, the frequency of monitoring the elevation change of each measuring point according to a certain frequency is 3 times/day to 1 time/2 days.
The invention has the advantages and effects that:
the monitoring device and the monitoring method realize regular monitoring of the vertical displacement of the deep soil body and the adjacent subway tunnel uplift in the deep foundation pit excavation process by using simple components so as to evaluate the problem of mutual influence in the urban rail transit construction and building construction processes, improve the understanding of the deep foundation pit excavation on the displacement field distribution of the adjacent soil body, and provide technical reference for industrial personnel.
Through considering monitoring to many factors such as different degree of depth foundation pits, different position relation (deep foundation pit and tunnel relative position relation), excavation time, the variety in the foundation pit excavation is paid attention to, the overall process of analysis foundation pit peripheral soil body displacement field space-time evolution.
The monitoring method overcomes the defects of the traditional monitoring project in time and space for measuring the displacement of the foundation pit soil body, and simultaneously monitors the displacement fields of the deep soil body inside and outside the deep foundation pit and the displacement field inside the tunnel, so that the considered factors are more comprehensive, and the method is more systematic.
The monitoring data is helpful for providing a special technical scheme for the investigation, design and construction of the near-subway foundation pit based on the deformation control of the subway tunnel, and the cost and time waste caused by excessive conservation for avoiding risks in the existing design and construction process is changed.
Drawings
FIG. 1 is a schematic view of a detecting member;
FIG. 2 is a schematic view of a monitoring rod in the detecting member;
FIG. 3 is a schematic view of an observation prism structure in the inspection unit;
FIG. 4 is a schematic view of an anti-tip concentric support structure in a detection member;
FIG. 5 is a schematic view of a protective sleeve in the detection member;
FIG. 6 is a schematic cross-sectional view of the monitoring of the present invention;
FIG. 7 is a schematic view of a monitoring profile during excavation;
FIG. 8 is a schematic monitoring plan view;
fig. 9 is a schematic view of a monitoring plane after excavation.
The components in the figure: 1 is a monitoring rod piece, 2 is an observation prism, 3 is an anti-tilting concentric support, 4 is a protective sleeve, 5 is filling sand, 6 is a concrete base, 1-1 is a threaded end, 1-2 is a hollow head end, 1-3 is a rod body main body, 2-1 is a prism end, and 2-2 is a threaded connection end.
Detailed Description
The invention is further explained below with reference to the figures and the examples.
As shown in fig. 1-5, the invention relates to a monitoring device for the influence of deep foundation pit excavation on the vertical deformation of a subway, and the members mainly comprise a monitoring rod member 1, an observation prism 2, an anti-tilting concentric support 3, a protective sleeve 4, a concrete base 6 fixed at the bottom of the monitoring rod member 1, filling sand 5 (auxiliary material) backfilled in the protective sleeve, and a red flag marked; the invention relates to a triangulation height measuring instrument (main measuring instrument) and a total station at the same time.
The monitoring rod piece 1 is a solid metal rod piece with a threaded end 1-1 at one end and a threaded hollow head end 1-2 at the other end, the length Li of each rod piece is 1000 mm-2500 mm, and the length Li is set according to a soil layer excavation progress plan. The length B of the hollow head end 1-2 is greater than the length dimension A1 of the threaded end 1-1. During assembly, the threaded end 1-1 at the lowest end is placed at the lowest end, the rod pieces are sequentially connected upwards and leak out of the ground to be not less than 0.5m, the threaded hollow end 1-2 is at the uppermost end, and the threaded connecting end 2-2 of the observation prism is screwed to the hollow end 1-2 of the monitoring rod piece. The effective length of each section of monitoring rod piece 1 is Li, accurate measurement and numbering of the rod piece are carried out after the processing is finished, the accuracy is 0.02 mm, the requirement is not high, and the width can be widened to 0.05 mm. The thread length a2 of the prism is less than the dimension B of the monitoring rod thread hollow head 1-2.
As shown in fig. 6-9, after the process of determining the supporting form of the deep foundation pit, firstly constructing a supporting pile, drilling a hole at a target measuring point to a depth 1-2m below the designed foundation pit depth before excavating for 1 week, placing a protective sleeve 4, pouring a small amount of concrete mortar into the sleeve 4 to form a base 6, inserting the assembled rod member 1 into the base 6 before initial setting, and adopting a concentric anti-tilting support 3 to ensure that the rod member is concentric with the sleeve 4 in the inserting process; filling sand 5 such as quantitative fine sand powder and the like into the sleeve uniformly, arranging an anti-tilting concentric support 3 every 0.5-2m until the port above the ground of the protective sleeve 4 is filled, and screwing the observation prism to the threaded hole 1-2 of the port. And arranging a striking small red flag next to the monitoring point so as to disturb the measuring point in the excavation process. Along with the excavation, one section of protective sleeve and one section of monitoring member can be removed when one layer of soil body is excavated.
2-4 monitoring sections (not less than 2) can be arranged on each foundation pit, and 3-5 measuring points are arranged on each section; correspondingly, in the subway tunnel, monitoring points are arranged at the junction of the extension line of the corresponding monitoring section and the tunnel in the extension range of the plane position of the foundation pit, and at least one measuring point is arranged outside the extension range of the plane position of the foundation pit. The horizontal distance between each monitoring point is preferably 10 m-30 m, and the monitoring points are arranged by deviating to one side of the tunnel. Therefore, the change rule of the vertical displacement field inside and outside the foundation pit and on the tunnel field space in the deep foundation pit excavation process is obtained.
At least 3 reference points and 1 working base point (set according to actual conditions) are respectively arranged above the ground and in the tunnel. For the datum point on the ground, the distance from the foundation pit to the empty surface should be not less than 2 times of the pit depth, and the elevation control point is not easily influenced by the external environment and is stable and reliable; an observation point outside a foundation pit (between the foundation pit and a tunnel) on the ground can be directly observed by a reference point, a stable and reliable deformation observation working base point needs to be established at the side of the foundation pit by an internal measurement point of the foundation pit, and the elevation change of the internal measurement point of the pit is monitored by adopting a triangular elevation measuring instrument. The elevation change of each measuring point in the tunnel is also based on the elevation change of each measuring point measured by a reference point far away from the foundation pit in the tunnel.
Before excavation of the foundation pit, initial value H of elevation of each measuring point to be measured ground rod piece observation prism 2ij1(i is the number of the measuring points; j is the number of the rod pieces of the measuring points, 1 is the first-time elevation value of the rod pieces of the measuring points j of the i), and the initial elevation values of the measuring points outside the foundation pit and in the tunnel; in the excavation process of each layer of soil body, monitoring the elevation change of each measuring point according to a certain frequency (3 times/day-1 time/2 days); when the excavation of each layer of soil is finished, before the next layer of soil is excavated, the elevation of the prism 2 of the soil monitoring rod piece 1 needs to be acquired, the rod piece, the prism 2 and the protective sleeve 4 are immediately detached after the acquisition is finished, the prism is installed on the next-stage rod piece, and the elevation is immediately acquired and used as an initial elevation value before the next layer of soil is excavated; the excavation of each layer of soil is carried out by collecting initial elevation value, multiple process elevation values and final elevation value, and the sum (L) of effective length of rod piece and prism size of elevation difference between the final elevation value of upper layer of soil and the initial elevation value of lower layer of soili+ a 3); and synchronously recording the excavation depth in the monitoring process for later analysis and comparison. After each monitoring, the relevant data is subjected to statistical analysis to obtain the accumulated deformation value delta Hi, the deformation rate (the ratio of the accumulated deformation value to the accumulated days) and the stage deformation value delta Hij and the deformation rate (the ratio of the stage deformation value to the stage days) of each measuring point, if the deformation rate or the accumulated deformation value reaches the warning standard, the monitoring frequency is increased, and the monitoring frequency is reported to each party of the project in time, and safety measures are taken if necessary.
During the excavation process, a striking mark (such as inserting a red flag, setting a fence and the like) is required to be arranged at each monitoring point, when large-scale equipment excavates accessories of the monitoring points, the large-scale equipment is required to avoid uniform excavation of a large slope, personnel in a side station command careful excavation, and manual excavation is adopted if necessary to prevent disturbance to the monitoring points. In the monitoring process, large equipment and vehicles are prevented from being in construction operation beside the working base point and the monitoring point, so that the monitoring result is prevented from being influenced by vibration. Table 1 is a data recording table of a monitoring section A taking the monitoring section A-A as an example of a pit internal measuring point A.
Data processing example:
A-A monitoring the 1 st measuring point in the section foundation pit and a first-stage analysis:
single deformation value: Δ H1ij = H1ij-H1i (j-1), j ≧ 2 (i.e., the difference between two adjacent monitored elevations);
step deformation accumulated value: Δ H11= Σ Δ H1ij = H1jn-H111+ ∑ Li;
stage deformation rate: ε 11= Δ H11/Δ D1= (H1 jn-H111+ ∑ Li)/(D1 j-D11);
a, monitoring a1 st measuring point in a section foundation pit and analyzing in a second stage:
single deformation value: Δ H1ij = H1ij-H1i (j-1), j ≧ 2 (i.e., the difference between two adjacent monitored elevations);
step deformation accumulated value: Δ H12= Σ Δ H1ij = H1gn-H1k1+ ∑ Li;
stage deformation rate: e 12= Δ H22/Δ D2= (H1 gn-H1k1+ ∑ Li)/(D2 j-D21);
and (3) accumulating the deformation value: Δ H1= Σ Δ H1i = H1gn-H111+ ∑ Lj;
cumulative deformation rate: e 1= Δ H12/Δ D12= (H1 gn-H111+ ∑ Lj)/(D2 j-D21);
A-A monitoring the 1 st measuring point in the section foundation pit and the nth stage analysis:
single deformation value: Δ H1ij = H1ij-H1i (j-1), j ≧ 2 (i.e., the difference between two adjacent monitored elevations);
step deformation accumulated value: Δ H1n = ∑ Δ H1ij = H1qn-H1p1+ ∑ Li;
stage deformation rate: ε 1n = Δ H1n/Δ Dn = (H1 qn-H1p1+ ∑ Li)/(Dnn-Dn 1);
and (3) accumulating the deformation value: Δ H1= Σ Δ H1i = H1gn-H111+ ∑ Lj;
cumulative deformation rate: e 1= Δ H12/Δ D12= (H1 gn-H111+ ∑ Lj)/(Dnn-D11);
wherein: sigma Li is the sum of the lengths of all measuring bars above the current measuring bar at each stage;
sigma Lj is the sum of the lengths of all measuring bars above the current measuring bar;
and the pit external measuring points and the tunnel internal measuring points count the stage deformation value, the accumulated deformation value, the stage deformation rate and the accumulated deformation rate according to the calculation method.
And (3) verifying the accumulated deformation of each measuring point: the (stage) deformation accumulation value can be obtained by summing two adjacent elevation differences (within a stage) and can also be obtained by considering the initial and last elevation differences of each stage of the rod length, and the two methods can be mutually corrected.
Drawing a data time course curve and a space distribution curve: according to the monitoring data, drawing a displacement time course change curve graph of each measuring point, thereby mastering the displacement change trend of all measuring points and the relation between the displacement change trend and the excavation stage; drawing a deformation rate time course chart of each measuring point, and mastering the relation between each measuring point and an excavation stage; and drawing a displacement distribution map on a certain section space at a certain stage of each measuring point, and analyzing the change distribution rule of foundation pit excavation on the displacement field of each measuring point.
And (3) error analysis: the error sources of the monitoring method are systematic error and random error, the systematic error mainly comes from the measuring instrument, and the error is generated due to the performance problem of the instrument and equipment, and the error cannot be avoided or eliminated; the random errors mainly comprise measurement errors caused by environments such as field temperature, humidity and the like, and meanwhile, different measurement personnel can generate certain measurement errors; in the monitoring method, the elevation error, the rod length error and the like generated in the process of dismantling two adjacent rods are crossed, so disturbance is avoided as much as possible when the rods are dismantled; meanwhile, the vibration of the mechanical equipment working on site can also influence the monitoring data; the excavation process should avoid producing great domatic at the monitoring point department to prevent that soil pressure from causing the slope to whole monitoring pole and producing the error.
Claims (8)
1. The utility model provides a deep basal pit excavation influences monitoring devices to subway vertical deformation which characterized in that: comprises a monitoring rod piece (1), an observation prism (2), an anti-tilting concentric support (3), a protective sleeve (4), filling sand (5) and a concrete base (6), one end of each monitoring rod piece (1) is provided with an outwardly protruding threaded end (1-1), the other end of each monitoring rod piece is provided with an inwardly recessed hollow head end (1-2), the monitoring rod pieces (1) are connected with the hollow head ends (1-2) through the threaded end (1-1) of the connecting rod pieces, the top of the connected monitoring rod pieces (1) is connected with the observation prism (2), the bottom of the monitoring rod piece is connected with a concrete base (6), a protective sleeve (4) is arranged outside the connected monitoring rod piece (1), the monitoring rod piece (1) is connected with the protective sleeve (4) through the anti-tilting concentric support (3), and filling sand (5) is filled between the monitoring rod piece (1) and the protective sleeve (4).
2. The device for monitoring the influence of excavation of the deep foundation pit on vertical deformation of the subway according to claim 1, characterized in that: the length of the hollow head end (1-2) is greater than that of the threaded end (1-1).
3. The device for monitoring the influence of excavation of the deep foundation pit on vertical deformation of the subway according to claim 1, characterized in that: the upper part of the observation prism (2) is a prism end (2-1), the bottom of the observation prism is provided with a threaded connection end (2-2), and the observation prism (2) is connected with a hollow head end (1-2) at the top of the monitoring rod piece (1) through the threaded connection end (2-2).
4. The device for monitoring the influence of excavation of the deep foundation pit on vertical deformation of the subway according to claim 1, characterized in that: the anti-tilting concentric supports (3) outside the monitoring rod piece (1) are arranged one by one at intervals of 0.5-2 m.
5. A method for monitoring the influence of excavation of a near-subway deep foundation pit on subway vertical deformation is characterized by comprising the following steps of: the method comprises the steps of constructing a support pile, installing a monitoring device, setting 2-4 monitoring sections on each foundation pit, and arranging 3-5 measuring points on each section; correspondingly arranging monitoring points at the junction of the extension line of the corresponding monitoring section and the tunnel in the extension range of the plane position of the foundation pit correspondingly in the subway tunnel, and respectively arranging at least one measuring point outside the extension range of the plane position of the foundation pit, wherein the horizontal distance between the monitoring points is 10-30 m and the monitoring points are arranged at one side of the tunnel; at least 3 reference points, 1 working base point and ground base point are respectively arranged above the ground and in the tunnelDirectly observing observation points outside the pit by means of datum points, establishing an observation working base point at the edge of the pit by using measuring points inside the pit, monitoring the elevation change of the measuring points inside the pit by adopting a triangular elevation measuring instrument, and measuring the elevation change of each measuring point inside the tunnel based on the datum points far away from the pit; before excavation of foundation pit, initial value H of elevation of each measuring point ground measuring rod piece observation prismij1Wherein: i is a measuring point number; j: numbering the rod pieces at the measuring points; 1, a first-time elevation value of a j rod piece of the i measuring point and an initial elevation value of each measuring point outside a foundation pit and inside a tunnel; monitoring the elevation change of each measuring point according to a certain frequency in the excavation process of each layer of soil body; when the excavation of each layer of soil is finished, before the next layer of soil is excavated, the elevation of the prism of the soil monitoring rod piece of the layer is collected, the monitoring device at the section is dismounted after the collection is finished, the prism is mounted on the next-stage rod piece, and the elevation is collected to be used as the initial value of the elevation before the next layer of soil is excavated; excavating each layer of soil, collecting an initial elevation value, a plurality of process elevation values and a last elevation value, and calculating the sum (L) of the effective length of a rod piece and the size of a prism according to the elevation difference between the last elevation value of the previous layer of soil and the initial elevation value of the next layer of soili+ a 3); and obtaining the accumulated deformation value delta Hi of each measuring point, the ratio of the accumulated deformation value, namely the deformation rate, to the accumulated days, and the ratio of the stage deformation value delta Hij to the deformation rate, namely the stage deformation value, to the stage days through the data.
6. The method for monitoring the influence of excavation of the near-subway deep foundation pit on subway vertical deformation according to claim 5, is characterized in that: the datum point above the ground is a stable and reliable elevation control point which is not less than 2 times of pit depth from the empty surface of the foundation pit and is not easily influenced by the external environment.
7. The method for monitoring the influence of excavation of the near-subway deep foundation pit on subway vertical deformation according to claim 5, is characterized in that: the method for installing the monitoring device comprises the steps of drilling a hole at a target measuring point to a depth 1-2m below the depth of a designed foundation pit before excavation, placing a protective sleeve, pouring a small amount of concrete mortar into the sleeve to form a base, inserting an assembled rod piece into the base before initial setting, and ensuring that the rod piece and the sleeve are concentric by adopting a concentric anti-tilting support in the inserting process; filling quantitative filling sand such as silty sand and the like into the sleeve uniformly, arranging an anti-tilting concentric support at intervals of 0.5-2m until the filling sand is filled at the port above the ground of the protective sleeve, screwing the observation prism into a port threaded hole, arranging a striking small red flag next to a monitoring point so as to disturb the measuring point in the excavation process, and removing a section of protective sleeve and a section of monitoring rod piece when excavating a layer of soil along with the excavation.
8. The method for monitoring the influence of excavation of the near-subway deep foundation pit on subway vertical deformation according to claim 5, is characterized in that: the frequency in the elevation change of each measuring point is monitored according to a certain frequency and is 3 times/day to 1 time/2 days.
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Cited By (3)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| CN113804153A (en) * | 2021-08-06 | 2021-12-17 | 上海隧道工程有限公司 | Liquid level control variable resistance type omnibearing telescopic device for monitoring deep soil deformation |
| CN113982049A (en) * | 2021-12-06 | 2022-01-28 | 上海宝冶工程技术有限公司 | Slope-releasing L-shaped prism reusable device and mounting method |
| CN114518639A (en) * | 2022-02-23 | 2022-05-20 | 广西北投交通养护科技集团有限公司 | Monitoring pile and method for automatically adjusting prism |
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| CN114518639A (en) * | 2022-02-23 | 2022-05-20 | 广西北投交通养护科技集团有限公司 | Monitoring pile and method for automatically adjusting prism |
| CN114518639B (en) * | 2022-02-23 | 2024-05-28 | 广西北投交通养护科技集团有限公司 | Monitoring pile and method for automatically adjusting prism |
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