| With the continuous development of road construction in scale and speed, there will be more and more constructions in deep and super long tunnels, and the geological conditions become more and more complex. With the constant development of the construction technology, it will provide technical support for tunnel safety and effective construction, and has great engineering value and social significance by comprehensive and in-depth research on all kinds of bad geological bodies in the tunnel and advanced method and means of prediction, guiding forecast work toward standardization, efficiency, energy conservation, improving the prediction accuracy, forming a special tunnel prediction method.The main content of this paper is construction method, mainly relying on Mi cangshan tunnel in Bashan highway and Zhegushan tunnel in Wenma highway. on the basis of the systematic study and analysis of the common method and applicability of the tunnel advanced geological prediction, set up a system of the comprehensive advanced geological prediction method. Based on summary of forecast data from predecessors, combining with practice of all kinds of bad geological interpretation symbol, fixed and summed up a set of tunnel advance geological prediction data comprehensive interpretation rules and set up a clear complete comprehensive advanced geological prediction method for geological analysis, geophysical exploration, combination of long-term forecasting and short-term forecasting. Good prediction effect is obtained, through the forecast practice. Some main achievements made in the research work are as follows:(1) Based on the analysis of principle on the tunnel advance geological forecast methods, such as constraints geology survey method, the seismic reflection method,the electromagnetic wave reflection method, resistivity test method and advanced drilling, got the applicability of several common forecasting methods, in combination with the principle characteristics and maneuverability of forecast method. Established a comprehensive prediction method system, which has a guiding ideology of taking geological analysis as the core, adopting the detection principle of long before short, special after macro, easy after difficult, continuing tofollow up the excavation verification. The method system can be mainly divided into three stages, geological data preparation stage, the forecast in the implementation stage, forecast validation and analysis summary stage. The implementation stage of the prediction of field work is divided into three levels. First of all, the constraints of geological logging and seismic reflection method are adopted to synthetically forecast. According to the geological record in the process of excavation section,submit the first level comprehensive geological forecast report of seismic wave reflection method to detect the results + constraints geological record. When the first level of comprehensive forecast results show the bad geological body in the front,survey forecast by the electromagnetic wave reflection method(or resistivity test method) and Submit the secondary comprehensive geological forecast report of seismic wave reflection method to detect the results + constraints geological record +electromagnetic wave reflection method to detect the results(or resistivity test results). When the secondary comprehensive prediction results show the possible geological disasters happen in the front, adopt advanced drilling to forecast and submit the third level comprehensive geological forecast report of seismic wave reflection method to detect the results + constraints geological record +electromagnetic wave reflection method to detect the results(or resistivity test results) + advanced drilling results. The purpose of the operation mode of the hierarchical forecast is to guarantee the quality of forecast, to improve work efficiency, and save the cost of construction.(2) According to the orderly, standardized and efficient advance geological forecast work, firstly put forward an advance geological forecast construction organization and management agency formed of construction unit, survey and design units, construction units, supervision units, forecast units and related scientific research units. At the same time, the duties of the participating units division of labor is defined and described in detail. And analyze and instruct the forecast working process of the construction organization and management agencies more comprehensively and detailed. How to specification division, itemized advance geological forecast work are described in detail, including constraints of geological logging, tsp advance forecast, geological radar and transient electromagnetic prediction, drilling in advance forecast and so on. Put forward the "Forecast forecast- validation- summary- again- revalidation- summary" forecast validation work cycle. On the one hand, verify the accuracy of the forecast results. On the other hand,conclude the accurate data processing method and interpretation key standards and constantly enhance the level of forecast, through the correct prediction of theV accumulation of experience and the analysis and correction of the causes of error prediction.(3) For the processing method of forecast data, the operation process of Data of TSP and geological radar data, drilling data processing in advance had been obtained, through the practical application and study. According to the characteristics of various forecasting methods, combining with the working practice,the field data acquisition and indoor data processing process analysis, summarizes the measures to improve the accuracy of forecasting method and experience.(4) For the forecast data interpretation techniques, starting with the basic geological characteristics of geological and geophysical characteristics of the analysis, summary all kinds of bad geological bodies in the catalog work and advance the abnormal characteristics in the process of drilling. Based on advance geological forecast related scientific research, the staff of seismic wave and electromagnetic wave to all kinds of bad reflection characteristics of geological research and results, combining with a variety of special forward modeling and typical test case, conclude Adverse geological system, detailed seismic wave and electromagnetic wave reflection characteristics analysis.(5) Put forward a set of match with the proposed comprehensive prediction method system of comprehensive integrated interpretation of the rules. The integrated interpretation rules are divided into three levels. There are 52 comprehensive interpretation results in the first level, 103 results in the second level,and 202 results in the third level. The technology is quite convenient with a A high degree of automation. The corresponding interpretation results can be obtained by using EXCEL document filtering function to data obtained from the corresponding work according to the corresponding input. It contains almost all may occur in the process of tunnel excavation geology, excellent versatility, and support in the use of modification at the same time.(6) Through the research above formed the comprehensive prediction method of the main content, preliminary apply in Micangshan tunnel and Zhege mountain tunnel. Excavation follow the geological record were coincident with the actual situation shows forecast and excavation program. Forecast results can satisfy the requirement of forecast work. The method shows that it has a better prediction effect and economic and technical benefits. The results can not only provide the future forecast of tunnel with systemic and normative guidance and basis, can also guide geological forecast interpretation work, improve the prediction accuracy, ensure the safety of tunnel construction, and has good economic and social benefits. |
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