CN104153391A - Open caisson geometrical shape monitoring method based on differential GPS - Google Patents

Abstract

The invention discloses a method for monitoring the geometry of caissons based on differential GPS. By setting up a GPS monitoring base station, the caissons are monitored during the process of floating, undocking, towing, mooring, sinking, and docking. Coordinates of the center, elevation, offset, torsion, elevation of blade foot, elevation of the river bed inside and outside the well, water velocity and flow direction, wave force and water level elevation, etc., through wireless networking, the GPS positioning measurement of each monitoring point on the top of the caisson The data is transmitted to the monitoring center in real time, the inclination and torsion angle are calculated in real time, the caisson deviation is obtained through the data monitoring method, the control command is issued, and the force of the cable is adjusted through the control device to achieve the deviation of the caisson. purpose of the correction. The monitoring method provided by the invention can realize the accuracy of monitoring the movement attitude of the caisson to the centimeter level, and has good control ability for real-time correction of the sinking deviation of the caisson.

Description

A monitoring method of caisson geometry based on differential GPS

technical field

The invention relates to caisson geometry monitoring, in particular to a caisson geometry monitoring method with centimeter-level precision and real-time wireless transmission. the

Background technique

The caisson tunnel is a large-scale cross-water traffic project that has been gradually developed since the beginning of the last century. At present, many cross-river and sea-crossing projects are under construction or planned in China. Most of the large-scale projects such as the island tunnel project of the Hong Kong-Zhuhai-Macao Bridge, the Qiongzhou Strait cross-sea project, the Yangtze River Estuary cross-river project, and the Penglai-Lushun sea-cross project have adopted the caisson tunnel scheme. The caisson tunnel consists of a number of prefabricated pipe joints, which are floated to the site and installed one by one. They are connected to each other underwater and correctly positioned in the excavated underwater foundation trench. For engineering construction, the key technologies for caisson tunnels mainly include foundation trench dredging and foundation treatment technology, pipe joint prefabrication technology, pipe joint floating and sinking technology, pipe joint joint design and pipe joint waterproofing technology. The floating and sinking of the caisson is affected by many aspects such as the speed and direction of the water flow, the tide, the density of the water, the waves, the strong wind, the characteristics of the tugboat, the characteristics of the waterway, the characteristics of the pipe joints, the mooring method, the towing scheme, and on-the-spot command. The construction is very complicated. , the risk is greater. The monitoring of stress, strain and overall stability during caisson towing and sinking has always been highly valued by the engineering community. Scholars at home and abroad have also conducted in-depth research. the

Zou Jingui analyzed the method of automatic monitoring of parameters such as the geometric position of the construction caisson, and implemented the automatic monitoring system of the construction caisson by using Visual C++ programming language and Access database system. the

Xiao Wenfu proposed the subsidence monitoring technology of the super large caisson in the middle tower of Taizhou Bridge, including the monitoring scheme of caisson cutting edge reaction force, side wall friction resistance, shaft wall and soil friction resistance, and anchor cable force, which provides a safe foundation for caisson construction. Timely and accurate forecast and early warning information. the

Zhu Jianmin conducted a monitoring study on the safety of drainage and subsidence of the north anchorage caisson of the Nanjing Fourth Yangtze River Bridge with the largest plane size in the world. According to the results of finite element analysis, a typical section is selected to monitor the change of tensile stress, which can find out the weak link of the structure and provide guidance for the safety monitoring of super large caisson sinking. Zhao Youming put forward the monitoring standard for the geometry and attitude of the caisson in the north anchorage of the Nanjing Yangtze River Fourth Bridge based on the code and the previous construction experience. the

Li Zongzhe proposed the monitoring technology for the sinking resistance of No. 6 caisson in the large caisson group of Xiangjiaba Hydropower Station. Through these monitoring data, the safe and stable sinking of the caisson is controlled. the

Chen Song established a monitoring model for the horizontal displacement of the loose cable saddle of the north anchorage caisson of the Jiangyin Yangtze River Highway Bridge from the three aspects of foundation displacement monitoring, foundation anti-sliding stability monitoring, and foundation soil stability monitoring. Force monitoring model and base reaction force monitoring model. the

At home and abroad, due to the limitations of technical conditions and monitoring components, the real-time monitoring of caisson towing and sinking is generally the monitoring of earth pressure through the monitoring of sinking resistance. At present, there is still a lack of monitoring systems and methods that can be accurate to centimeter-level monitoring and provide real-time collection and wireless transmission. the

Contents of the invention

The present invention aims at the defects existing in the existing methods, and provides a caisson geometry monitoring method based on differential GPS, the coordinates, elevation, deviation, torsion, blade foot elevation, river bed surface elevation inside and outside the well, water level of the caisson center, etc. Parameters such as flow velocity and direction, wave force and water level are transmitted wirelessly to calculate the inclination and torsion angle attitude in real time, and to correct the offset of the caisson. the

In order to achieve the above object, the present invention adopts the following technical solutions

The caisson geometry monitoring method based on differential GPS, the method comprises the following steps:

(1) Four monitoring points are arranged around the top of the caisson as shown in Figure 2. The points can be considered according to the site conditions, and the measurement point marks are set up, and the GPS receiver antenna is installed. Together with the GPS reference station placed on the shore, it constitutes Real-time dynamic relative positioning;

(2) Establish a sinking GPS reference station for steel caissons, and establish a monitoring base station at the trestle bridge for real-time monitoring of caissons;

(3) The system transmits the GPS positioning measurement data of each monitoring point on the top of the caisson to the monitoring center in real time through wireless networking;

(4) Measure the construction plane position of the caisson. According to the construction site conditions and construction technology, the geometric monitoring mainly adopts the high-efficiency, high-precision, high-reliability and low-consumption differential global satellite positioning system (DGPS) for plane position measurement, and checks with the measurement results of the total station;

(5) Monitor caisson displacement. According to the plane positioning results of the caisson, the positioning results of the four GPS points around the caisson are compared with the theoretical results to obtain the x, y coordinate difference of each monitoring point, and the point displacement is calculated, using the GPS points around the caisson The coordinates of the caisson center are calculated from the coordinates, and compared with the design position of the caisson center, the overall displacement of the caisson center can be obtained;

(6) Measure caisson elevation. Select 2-3 elevation control points on the shore, and place a GPS receiver on them. After the other receiver is initialized, measure the geodetic height of the caisson axis points respectively according to the GPS-RTK method, which can be obtained according to the above weighted average method principle normal height;

(7) Measure and control caisson inclination value. By monitoring the elevation of the control point of the caisson axis, the inclination of the caisson is calculated. Calculate the caisson inclination by comparing the height difference and distance between points 2 and 4 and points 1 and 3;

(8) Calculate caisson torsion. According to the coordinates of axis control points 1′, 3′ or 2′, 4′ measured after the caisson sinks in place, the angle between them and the bridge axis is obtained, which is the torsion angle of the caisson. the

The invention utilizes the differential GPS technology to process the geometry of the monitored caisson with high precision, so that the monitoring accuracy can reach centimeter level, and the real-time correction of the sinking deviation of the caisson has good control ability. the

Description of drawings

The present invention will be further described below in conjunction with the accompanying drawings and specific embodiments. the

Fig. 1 is a flowchart of the present invention

Figure 2 is a schematic diagram of the arrangement of GPS measuring points on the top of the caisson

Figure 3 is a schematic diagram of caisson GPS observation

Figure 4 is a schematic diagram of steel caisson torsion measurement

Detailed ways

In order to make the technical means, creative features, goals and effects achieved by the present invention easy to understand, the present invention will be further described below in conjunction with specific illustrations. the

High-precision, real-time wireless transmission is the key to caisson geometry monitoring. For this reason, the present invention provides a kind of caisson geometry monitoring method based on differential GPS, and the method comprises the following steps (as shown in Figure 1):

(1) Four monitoring points are arranged around the top of the caisson as shown in Figure 2. The points can be considered according to the site conditions, and the measurement point marks are set up, and the GPS receiver antenna is installed. Together with the GPS reference station placed on the shore, it constitutes Real-time dynamic relative positioning. the

(2) Establishment of GPS reference station for steel caisson sinking

Set up a monitoring base station at the trestle bridge for real-time monitoring of caissons. the

Except the described mode of claim 3, it is characterized in that, also comprise realizing a plurality of monitoring point synchronous acquisitions. the

(3.1) Set the corresponding IP protocol, through the wireless network, the data from each monitoring point is received by the omnidirectional antenna, and then transmitted to the data processing center;

(3.2) The interface standard adopted by GPS receiver is RS-232 serial interface, and the wireless spread spectrum communication network is RJ-45 interface;

(3.3) Through the serial port communication equipment server based on the IP protocol, the protocol conversion can be realized, and a single-point to multi-point wireless communication system can be formed to realize synchronous collection of multiple monitoring points. the

In addition to the method described in claim 4, it is characterized in that it also includes setting up a GPS measurement control and calculation center in the monitoring room, and transmitting the measurement parameters and data of the base station and the mobile station through the wireless local area network at any time, and analyzing and processing at the control center , to get the plane position of each monitoring point. the

(5) Monitor caisson displacement. According to the plane positioning results of the caisson, the positioning results of the four GPS points around the caisson are compared with the theoretical results to obtain the x, y coordinate difference of each monitoring point, and the point displacement is calculated, using the GPS points around the caisson The coordinates of the caisson center are calculated from the coordinates, and compared with the design position of the caisson center, the overall displacement of the caisson center can be obtained;

(6) Measure caisson elevation. Select 2-3 elevation control points on the shore, and place a GPS receiver on them. After the other receiver is initialized, measure the geodetic height of the caisson axis points respectively according to the GPS-RTK method, which can be obtained according to the above weighted average method principle normal height;

In addition to the method described in claim 7, it is characterized in that it also includes that when the concrete is poured, the relative inclination between the upper and lower sections needs to be measured immediately after each pouring of concrete, and an instant three-dimensional model is established, In order to obtain the real three-dimensional posture of the caisson in the end. At the same time, use the vertical ball to detect the inclination of each caisson in real time, measure the inclination of the top of each caisson and the top of the previous caisson to calculate, and make a record. After each welding, the The impact and law of the caisson in the lower section on the caisson in the upper section shall be corrected in advance. The sinking depth, plane position and deflection of the caisson are monitored by total stations, levels, automatic elevation monitoring micro-pressure sensors and inclinometers. the

In addition to the method described in claim 8, it is characterized in that after the caisson is sunk in place, the coordinates of the top axis control point of the caisson can be measured directly by using the GPS-RTK measurement mode. At the same time, the polar coordinate method of the total station is used for checking to ensure the accuracy of the measured data. The schematic diagram of steel caisson torsion measurement is shown in Fig. 4. the

The basic principles, main features and advantages of the present invention have been shown and described above. Those skilled in the art should understand that the present invention is not limited by the above-mentioned embodiments, and that described in the above-mentioned embodiments and the specification only illustrates the principles of the present invention, and the present invention will also have other functions without departing from the spirit and scope of the present invention. Variations and improvements are possible, which fall within the scope of the claimed invention. The protection scope of the present invention is defined by the appended claims and their equivalents. the

Claims (1)

1. the open caisson geometric shape method for supervising based on differential GPS, is characterized in that realizing high accuracy, calculates also wireless transmission open caisson geometric shape in real time, and the method comprises the steps:

(1) lay some control points in the surrounding on open caisson top, obtain the GPS position data of open caisson;

(2) set up steel well sinking GPS datum station;

(3) obtain plane coordinates and the elevation of each control point;

(4) by wireless networking mode, the gps position measurement real-time data transmission that open caisson is pushed up to each control point is to Surveillance center;

(5) measure open caisson construction plan-position; The displacement of monitoring open caisson; Measure open caisson elevation;

(6) Trigonometric Leveling by Total Station is carried out checking measurements;

(7) open caisson displacement monitoring;

(8) measure open caisson tilting value;

(9) calculate open caisson twist;

(10) open caisson off normal amount is revised.