A Study on the Implementation Path of the Blended Teaching Model in Geological Hazards Investigation and Evaluation

Geological Hazards Investigation and Evaluation is the core course of Environmental Geological Engineering,aiming to cultivate skilled talents with solid theoretical knowledge and excellent practical skills.At present,the course faces several issues,including a teaching environment disconnected from real-world work scenarios,course content that deviates from job-related tasks,a lack of digital teaching resources,and reliance on a single teaching method,leading to students’poor feedback from employers.Based on the concept of outcome-based education,the course team of Geological Hazards Investigation and Evaluation establishes a“five-step double-rotation”blended teaching model with the help of a Small Private Online Course platform.The program is designed to improve the teaching environment and expand the digitalized teaching resources in order to improve students’learning motivation,enhance learning effectiveness,and cultivate skillful talents who meet employers’satisfaction.

China's Shale Gas Geological Investigation and Prospecting Have Made Significant Progress

Since 2015, the China Geological Survey has implemented a major program of ＂Geology Survey of Land Energy Mineral Resources＂. Till now, a total of billions of RMB have been invested and seven engineering projects have been established, all of which has greatly enhanced the geological survey and exploration of China＇s continental shale gas in an attempt to overcome the oil and gas shortage.

Engineering Geological Investigations for the Foundations of Large Structures-Examples of a Concrete Dam and a long Bridge in Portugal

The safety of large structures requires adequate foundations, which implies a good knowledge of the geological and geotechnical conditions of the respective ground. In general, that is only possible through engineering geological studies which include proper site investigation techniques, adapted to the nature of the ground (rock mass or soil) and to the associated engineering problems. The paper illustrates the studies carried out for the design of the foundations of Ribeiradio 76 m high concrete gravity dam in a difficult rock mass and of Vasco da Gama Bridge, 13 km long, crossing the Tagus River in Lisbon, Portugal, through piles 75 m deep.

Comparative study of different machine learning models in landslide susceptibility assessment: A case study of Conghua District, Guangzhou, China

Machine learning is currently one of the research hotspots in the field of landslide prediction.To clarify and evaluate the differences in characteristics and prediction effects of different machine learning models,Conghua District,which is the most prone to landslide disasters in Guangzhou,was selected for landslide susceptibility evaluation.The evaluation factors were selected by using correlation analysis and variance expansion factor method.Applying four machine learning methods namely Logistic Regression(LR),Random Forest(RF),Support Vector Machines(SVM),and Extreme Gradient Boosting(XGB),landslide models were constructed.Comparative analysis and evaluation of the model were conducted through statistical indices and receiver operating characteristic(ROC)curves.The results showed that LR,RF,SVM,and XGB models have good predictive performance for landslide susceptibility,with the area under curve(AUC)values of 0.752,0.965,0.996,and 0.998,respectively.XGB model had the highest predictive ability,followed by RF model,SVM model,and LR model.The frequency ratio(FR)accuracy of LR,RF,SVM,and XGB models was 0.775,0.842,0.759,and 0.822,respectively.RF and XGB models were superior to LR and SVM models,indicating that the integrated algorithm has better predictive ability than a single classification algorithm in regional landslide classification problems.

Clogging of slurry-shield tunnel-boring machine drives in sedimentary soft rock:A case study

This paper presents a case study of the clogging of a slurry-shield tunnel-boring machine(TBM)experienced during tunnel operations in clay-rich argillaceous siltstones under the Ganjiang River,China.The clogging experienced during tunneling was due to special geological conditions,which had a considerably negative impact on the slurry-shield TBM tunneling performance.In this case study,the effect of clogging on the slurry-shield TBM tunneling performance(e.g.,advance speed,thrust,torque,and penetration per revolution)was fully investigated.The potential for clogging during tunnel operations in argillaceous siltstone was estimated using an existing empirical classification chart.Many improvement measures have been proposed to mitigate the clogging potential of two slurry-shield TBMs during tunneling,such as the use of an optimum cutting wheel,a replacement cutting tool,improvements to the circulation flushing system and slurry properties,mixed support integrating slurry,and compressed air to support the excavation face.The mechanisms and potential causes of clogging are explained in detail,and the contributions of these mitigation measures to tunneling performance are discussed.By investigating the actual operational parameters of the slurry-shield TBMs,these mitigation measures were proven to be effective in mitigating the clogging potential of slurry-shield TBMs.This case study provides valuable information for slurry-shield TBMs involving tunneling in clay-rich sedimentary rocks.