A synchronous jacking system and jacking method for box culverts passing under existing lines

Abstract

The invention provides a synchronous jacking system for underneath passing an existing line box culvert. A plurality of jack groups, which are arrayed to form one row along a jacking direction, are arranged, so that the frequency of increasing cushion blocks between a rear wall and the jack groups is reduced and the jacking errors are reduced; the requirements on piston rod routes of the jacks are reduced and an applicable range of equipment is enlarged. According to a synchronous jacking method provided by the invention, reversing time of a reversing valve connected with each jack is controlled through a controller to be gradually increased along a direction from small displacement to large displacement of the box culvert, so that the jacking force of each jack is gradually increased along a direction from the large displacement to the small displacement of the box culvert in a synchronous jacking adjusting process; each jack has a stopping action, so that each jack can be independently and accurately controlled and the synchronous adjusting process can also be divided into a plurality of small routes according to requirements; the adjusting process is more accurate and controllable and aims of reasonably adjusting and correcting in real time are realized.

Description

technical field [0001] The invention relates to tunnel jacking construction equipment, in particular to a synchronous jacking system and jacking method for a box culvert passing under an existing line. Background technique [0002] The box culvert passing through the existing line is mostly constructed by jacking method, and the jacking construction process is as follows: ①Excavate the work pit, pour the slide plate → ② Prefabricate the box culvert body on the slide plate → ③ Build the back wall and reinforce the existing line → ④Install the jacking equipment and jack the box culvert→⑤After completing a jacking process, place the jacking column in the neutral position→⑥Cycle until the jacking is in place. The jacking method construction can reduce the disturbance to the existing lines, does not interrupt the operation of the existing lines, and has the advantages of simple method, safety and reliability. [0003] "CJJ74-99 Regulations for Jacking Construction and Acceptance...

AI Technical Summary

Problems solved by technology

[0005] (1) Excessive lateral deviation of the box culvert leads to over-excavation of cut soil on one side and under-excavation on one side

Even if it can be corrected and corrected, a large area of ​​cavities will be formed on the side of the over-excavation, causing additional settlement of the existing line, and in severe cases, cracking on the top surface of the line

[0006] (2) After the lateral deviation is too large, the deviation correction will cause the local force on the side of the front end soil cutting equipment (shield machine, blade angle) of the box culvert to be too large, resulting in abnormal deformation and causing the concrete damage of the main body of the box culvert

[0007] (3) Once the deviation exceeds the limit, it is very difficult to correct the deviation. Forced deviation correction will cause inelastic deformation and cracks in the box culvert bridge body and the front-end soil cutting equipment, which will cause great harm. If no measures are taken, the box culvert will increase with the jacking length. increase, the deviation from the central axis of the design is getting more and more serious, and it cannot be connected with the intercommunication line

[0008] (4) The existing jacking equipment is composed of two parts: the hydraulic system and the jacking force system. The jacking equipment converts the readings of the oil pressure gauge into the jacking force data and manually reads the displacement data of the jack, so the error is relatively large

The lateral deviation depends on manual monitoring and measurement. Once the number of box culvert sections is large and the length of the sections is large, it will be a huge test for the responsibility and professional level of the surveyors. Moreover, the manual measurement efficiency is low and the frequency is low, so it is impossible to timely control the center line of the box culvert Deviation

[0009] (5) After the jacking of the oblique box culvert with cut soil, a force couple is formed due to the different lengths cut into the soil on the left and right sides, forcing the box culvert to be laterally displaced along the acute angle side, and the left and right sides have to be jacked up with the increase of the soil eating depth. The position of the picks is adjusted, but the existing jacking equipment cannot collect data such as the jacking force and displacement of each jack in real time. Under the current technical conditions, the jacks are basically arranged symmetrically or asymmetrically with the center line of the box culvert, and the position adjustment of the jacks is relatively blind , adjustments often fail to meet reasonable requirements

[0010] Chinese patent 200510111406.8 discloses a computer synchronous propulsion method and device, which uses a computer-controlled hydraulic system to manipulate the jack group to complete the synchronous jacking of the box culvert. The solution only mentions that displacement sensors are installed on the left and right sides of the box culvert for For the displacement of the left and right sides of the box culvert, if the displacement is large, reduce the speed of the oil cylinder on the side with the large displacement, and if the displacement is small, increase the speed of the cylinder on the side with the small displacement. The specific detailed synchronous adjustment of the oil cylinders is not disclosed in this plan method and process

[0011] To sum up, it is very important to control the lateral deviation in the box culvert passing under the existing line. However, although the displacement synchronization can be realized under the existing technical conditions, it cannot be "reasonably adjusted" and "real-time deviation correction" in the process of displacement synchronization adjustment. , the box culvert is prone to large lateral deviation, therefore, a solution is needed to solve this problem

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