The review meeting for the special plan on advanced geological forecasting and monitoring of the Dejiang Tunnel was held at our company.

Release time:

2016-11-12 08:48

Source:

On November 10, our company hosted a special review meeting for the advanced geological forecasting and monitoring plan of the Dejiang Tunnel on the De-Wu Expressway. Leaders from the Guizhou Provincial Department of Transport, the Provincial Quality Supervision Bureau, the Provincial Highway Bureau’s High-Speed Construction Office, as well as specially invited experts in geology and tunnel engineering, representatives from the construction and supervision units of the Dejiang Tunnel, and relevant personnel from our company and its subsidiary, Guizhou Hongxin Chuanda Engineering Testing & Consulting Co., Ltd., attended the meeting.

This special review meeting on advanced geological forecasting and monitoring measurements for tunnels is the first of its kind in Guizhou Province. In order to implement the requirements of the “Notice from the Guizhou Provincial Department of Transport on Further Strengthening Geological Forecasting and Monitoring Measurements for Highway Tunnels” (Qian Jiao Zhi [2015] No. 2), and actively carry out the work directives recently put forward by leaders from the Provincial Department of Transport and the Provincial Quality Supervision Bureau at the Dejiang Tunnel site, Hongxin Chuanda has proactively organized and meticulously prepared this special plan for geological forecasting and monitoring measurements.

For the first time, the special plan introduces safety risk assessment into forecasting and monitoring. Based on the varying engineering geological and hydrogeological conditions across different tunnel sections, a segmented design approach is adopted. Sections are divided according to their geological complexity and risk assessment levels, with particular emphasis placed on key segments. Moreover, in line with the principle of dynamic design, the classification of geological complexity for each tunnel section and the corresponding forecasting methods and technical requirements will be adjusted promptly based on the geological information obtained during the forecasting and implementation process.

The participating leaders and expert panel unanimously agreed that, in areas characterized by the Wenxin Zheng Fault, lithological interfaces (particularly the boundary between soluble and non-soluble rocks, as well as weak interbeds), karst features (including sudden mudflows, water bursts associated with corrosion, and collapses caused by instability of karst conduit fillings), rock mass fracturing and groundwater development zones induced by the Changfeng Anticline and Shichao Syncline, fault fracture zones and differential weathering fracture zones, and tunnel sections prone to water inrushes and sudden water bursts due to confined aquifers and underground dark rivers, a comprehensive advanced geological forecasting approach should be adopted—primarily relying on geological surveys, supplemented by geophysical exploration methods, and centered around advanced geological drilling. At the same time, the participating leaders and expert panel unanimously concluded that, during the implementation of monitoring and measurement, while carrying out routine mandatory monitoring items, it is also necessary to conduct detailed monitoring of internal displacements within the surrounding rock, pressures between the surrounding rock and initial support structures, internal forces in steel supports, stresses in secondary lining concrete, and seepage pressures, especially in key sections, thereby providing long-term monitoring for the Dejiang Tunnel.

After review by the expert panel, the special implementation plan for advanced geological forecasting and monitoring during the construction of the Dejiang Tunnel is well-founded, employs appropriate standards, and its content is basically complete. The methods and measures for advanced geological forecasting and monitoring and in-situ monitoring are generally reasonable, and the plan is feasible. (Text/Photos: Liu Zhiguo)