【 Outstanding Case 】 Topcon 3D Paving Becomes an "Accelerator" for the High-quality Construction of Xi 'an Outer Ring Expressway Project

Topkang 3D paving facilitated the smooth implementation of the Xi 'an Outer Ring Expressway during the epidemic

The southern section of Xi 'an Outer Ring Expressway is a key expressway construction project in Shaanxi Province. It started full-scale construction in December 2018. Among them, the key control project, the Bailuyuan Tunnel, was initiated in advance in December 2017. The project is constructed by Shaanxi Provincial Transportation Group, with Xi 'an City responsible for land acquisition and demolition, construction environment guarantee and other work.

The construction section starts from the 鄠 county district of xi 'an, connecting with the already completed northern section of xi 'an Outer Ring Expressway at the 鄠 county east Hub Interchange. It passes through Xi 'an High-tech Zone, Chang 'an District and Lantian County, and ends on the east side of the Lantian East Interchange of the Shanghai-Xi 'an Expressway in Lantian county, with a total length of 70.16 kilometers. The current construction section that adopts the Topcon 3D mmGPS paving control system is the pavement project undertaken by the Second Work Area of the ZS-1 section, starting from the Yinzhen Interchange in Chang 'an District.

Starting from April 17, 2022, during the dual-machine continuous paving construction of the water-stabilized layer in this project, the second work area of the ZS-1 section pavement project was the first to adopt the Topcon 3D mmGPS paving control system in conjunction with two Vogler SUPER 1880L pavers for precise paving control of the water-stabilized layer.

Since the start of construction, the Topkang 3D paving system has received unanimous praise from the project party for its stable performance, millimeter-level paving accuracy, high-standard smoothness effect, and automated control during the paving process in multiple construction sections such as the main line and the Yinzhen Service Area.

Traditional 2D sliding boots are usually made by setting up steel wire ropes. Precision errors are caused by the self-contamination of the steel wire rope, its elasticity and deflection, etc. When the paver is working by increasing the throttle to transport materials, the shaking of the vehicle body will cause the sliding boots to jump on the wire rope. Coupled with the deflection error caused by the sagging of the wire rope itself, the elevation is only accurate at the position close to the pile column, but there may be a significant error at the position between two pile columns. This will lead to the transmission of data with errors to the paver, causing the screed to be adjusted too frequently. As a result, the paved road surface will show a certain degree of undulation, making it difficult to effectively ensure smoothness.

The Topcon 3D paving control system, through high-precision measurement systems such as the global satellite navigation positioning system and millimeter-level domain laser, three-dimensionally controls the planar position and elevation accuracy of paving operations. Combined with technologies like automated control, 3D digital modeling, and wireless communication, it has completely broken free from the constraints of traditional steel wire ropes and achieved pile free operations. It avoids problems such as human error, steel line sagging and pollution, and sensor jumping during traditional steel line hanging construction. It effectively controls the thickness, elevation and flatness of the pavement structure layer, and the elevation error is controlled at the millimeter level.

The mmGPS mobile station that comes with the system can monitor the construction situation in real time. It is an effective means to achieve dynamic quality management of construction operations, ensuring construction quality. It eliminates essential construction steps such as manual pile driving and layout, as well as wire drawing for setting benchmarks, reducing the influence of human factors and the pre-preparation time for paving. While significantly saving human input, it also greatly improves the paving quality and work efficiency. It is also an important technical guarantee to ensure the smooth implementation of the project in the current domestic environment where the epidemic is spreading.

The Topcon 3D paving system adopts GNSS satellite positioning + domain laser control system for paving accuracy. This system is not affected by environmental lighting conditions during operation and can achieve 24-hour continuous operation. Throughout the process, it precisely controls the absolute elevation of each layer of pavement paving, which can reduce the waste of high-quality materials. It can ensure the quality, thickness and smoothness of pavement paving while maintaining the paving quality, thickness and flatness Realize precise paving construction without piling, digitalization and intelligence.

The features and advantages of Topcon 3D mmGPS paving Control system:

Pile-free paving

01

There is no need for on-site measurement personnel to place piles and set up reference baseline lines, reducing on-site line hanging, beam erection and other procedures, reducing the input of auxiliary personnel, making on-site management more efficient and improving safety.

All-weather construction operation

02

The system's box-making screen displays the current construction status, which is simple and easy to understand, facilitating the operator's viewing. The construction conditions are not affected by light, allowing for continuous 24-hour construction operations.

Elevation accuracy at the millimeter level

03

Millimeter-level elevation control accuracy provides a high-precision elevation reference for the entire construction process, avoiding the waste of high-quality materials.

LaserZone technology

04

Based on Topcon domain laser technology, a single domain laser emitter can simultaneously provide millimeter-level domain laser signals to all domain laser receivers (PZS-MC on the paver and PZS-1 on the mmGPS rover) within a 10m (height) *300m (radius) area.

The 1+N working mode ensures good sharing of benchmark data

05

Unlike the one-to-one original working mode of the previous generation 3D paving system, the control reference of Topcon mmGPS paving system adopts a real-time data sharing mechanism. A single domain laser emitter and GNSS base station can simultaneously provide high-precision 3D positioning signals for multiple devices, improving the efficiency of on-site data utilization and the convenience of operation. Minimize the input of professional equipment and personnel to the greatest extent;

Good system compatibility

06

The 3D mmGPS paving control system features a plug-and-play design. It does not require any modification to the mechanical hydraulic system and is directly compatible with all mainstream domestic and imported brands of pavers on the market. Moreover, there is no need for any paver manufacturer to separately open an authorization code.

Full-process control of paving operations

07

Combined with the 1+N working mode, Topcon's millimeter-level mobile station can conveniently achieve full-process control of the entire paving operation. The digital model of road design can be inspected in advance, the paving process can be detected in real time, and the re-inspection and acceptance after paving can be carried out, thereby achieving quality control throughout the construction process and real-time control of the paving work quality.