To accurately obtain the tensile strength of rock and fully understand the evolution process of rock failure is one of the key issues to the research of rock mechanics theories and rock mass engineering applications. Using direct tensile, Brazilian splitting, and three‐point bending test methods, we performed indoor and numerical simulation experiments on marble, granite, and diabase and investigated the tensile strength and damage evolution process of several typical rocks in the three different tests. Our experiments demonstrate that (1) the strength is about 10% greater in the Brazilian splitting than in the direct tensile, while the tensile modulus is lower; it is the highest in the three‐point bending, which is actually subjected to the bending moment and suggested as one of the indexes to evaluate the tensile strength of rock; (2) the strength in splitting tests is strikingly different, while the strain law is basically similar; the direct tensile test with precut slits is more attainable than that with no‐cut slits, with an uninfluenced strength; (3) the failure modes of rocks using different methods are featured by different lithology, while their final modes are basically the same under the same method; (4) PFC and RFPA numerical simulation tests are effective to analyze the internal crack multiplication and acoustic emission changes in the rock as well as the damage evolution process of rock in different tests.

Hazardous rock refers to an unstable rock block that is cut by weak structural planes and gradually separates from the slope. Hazardous rock generally collapses rapidly, and at present, it is challenging to effectively identify the separation degree of the rock and accurately predict its sudden failure. In this study, focusing on a hazardous rock with tilt behavior, a microelectromechanical system (MEMS) acceleration sensor is used in combination with the calculation principle of the included angle of the space vector to establish a microtilt angle monitoring method. A physical model test is designed, in which a thermally sensitive material (with heat‐sensitive strength) is adopted as the weak structural plane of the hazardous block, and the change in the tilt angle during the process of block instability is monitored at a sampling frequency of 1000 Hz. The test results show that the accelerated evolution of the tilt angle is a precursor to hazardous rock failure. In the rapid acceleration stage, the reciprocal of the tilt angle rate is approximately linear with time, and a correlation equation is obtained. Assuming that the change rate of the tilt angle is approximately infinite, the failure time of hazardous rock can be predicted using the correlation equation. In addition, the effectiveness of the instability prediction method based on microtilt angle monitoring is verified by analyzing the long‐term monitoring data of hazardous rock.

Debris flow is a geological process primarily triggered by factors such as rainfall or earthquakes, characterized by strong abruptness and significant destructive force. It poses a severe threat to human life and property. Exploring its formation, initiation mechanisms, and effective early warning measures is a reliable approach for disaster prevention and mitigation in mountainous regions. An indoor simulation experiment system was designed to study the initiation process of coarse-grained gravel-type debris flow under different particle sizes and slope angles. The interplay among the mean particle size, water flow, the slope angle of the material source, and the onset of debris flow has been elucidated to assess the dynamic changes in various characteristic parameters. This analysis formed initiation criteria specific to gravel-type debris flow. The combined particle size and slope angle of the material source were positively correlated with the water power required for debris flow initiation. A fitting relationship between the unit width flow rate, mean particle size, and slope angle was established. The humidity, seepage pressure, soil pressure, slope angle, and vibratory shock acceleration of the material source had characteristics such as mutability or asynchronism during the formation and initiation of debris flow. However, humidity and seepage pressure were not used as initiation criteria. The initiation criteria for debris flow included changes in characteristic parameters (e.g., soil pressure, slope angle, and vibration acceleration). The research findings can provide a reference for the characteristic identification and initiation early warning of similar types of debris flows, enhancing the safety management level of debris flow disasters.

Before the engineering design and construction of highway tunnels, it is necessary to carry out detailed investigations on the geographical layer distribution, dysplasia structural conditions, groundwater and other geological conditions in the engineering region, which can provide security for the engineering construction and service of the project. High-density electric method is an array type rapid exploration method. It has the advantages of measuring points easily setting, automatic data acquisition, rich information interpretation, short survey period and low cost. After more than 30 years of development and application, it is widely used and effective in engineering survey field. With the using AGI high-density resistivity imaging system, the geological conditions and poor structures of the Pine Mountain tunnel project of the 108 National Highway in the Jingxi Mountainous Area were investigated and implemented, and a variety of measuring devices were selected for comparative testing and data inversion analysis. By comparing the test results with the geological data and the situation on the site, it is inferred that more accurate information on stratigraphic structure and abnormal body distribution can make up for the serious shortage of engineering geological drilling points.

Compared with the traditional landslide monitoring and early warning technology, landslide emergency monitoring and early warning based on situation awareness sensing has the advantages of active sensing, real-time online diagnosis, combination of timing and triggering acquisition and monitoring. Through the comparison and analysis of the engineering application and traditional technology, this paper shows that the system applies the concept of situation awareness to the field of landslide emergency monitoring effectively and accurately. Besides, the vibration and tilt change of the landslide deformation body is obviously earlier than that of displacement, so it is better to monitor the vibration and tilt change of the landslide deformation body than the change of the displacement of the landslide deformation body.

In mountainous areas, dangerous rock mass collapse is a serious threat to human life and property safety. However, how to effectively prevent and control the instability of dangerous rock mass is still an urgent unsolved problem. In this study, the dynamic characteristics of dangerous rock mass under constant micromotion were analysed from the perspective of elastic wave propagation. When the slip plane of the dangerous rock mass is damaged, many micropores and cracks will appear in the medium composed of the slip surface. With constant micromotion as the vibration source, the elastic wave propagates to the dangerous rock mass through the damaged slip plane. The high-frequency components of elastic waves scatter in pores and fissures, where energy dissipates. According to this characteristic, a laboratory simulation experiment was designed. In the experiment, the damage process of the slip plane was simulated by the freeze‒thaw process of frozen hydrosol. The experimental analysis showed that the centre frequency of the high-frequency part of the dangerous rock mass model and bedrock mass model decreased as the frozen surface continued to melt. As the dangerous rock mass model and the bedrock mass model continued to fit, the centre frequency of the high-frequency part of the two rock mass models rebounded. This phenomenon showed that the damage degree of the slip plane between the dangerous rock mass and the bed rock mass can be effectively reflected by the centre frequency of the high-frequency part of the two rock mass models. During the experiment, the dangerous rock mass did not slide in the whole process, indicating that the deformation index has difficulty reflecting the stability of the hidden dangerous rock mass. In addition, the application conditions of using the natural frequency characteristics of dangerous rock mass and the scattering characteristics of elastic wave in the damage identification of structural plane were analysed: (1) when the structural plane has macrofracture, the change of natural frequency of dangerous rock mass should be used to analyse the damage degree of structural plane; (2) when there is no macrofracture of the structural plane, the characteristics of elastic wave scattering should be used to analyse the damage degree of the structural plane. This study provided a new idea for the prevention and control of dangerous rock masses and is expected to provide a useful reference for the automation of dangerous rock mass prevention and control.