AbstractThe mechanical properties of a coal–rock body were examined through uniaxial compression tests, and the rupture process of the coal–rock body was monitored in real time using a combined acoustic emission (AE) monitoring system and a digital image correlation (DIC) full-field strain measurement system. From a comparison of the mechanical properties of coal and sandstone, clear differences are apparent regarding the uniaxial compressive strength, deformation characteristics, and damage mode; the brittle failure characteristics of the coal samples are also more evident. The change in AE energy reflects the accumulation and release of elastic energy during the rupture process, and the evolution of AE localization points under different stress levels can effectively reflect rupture propagation. Further, the DIC full-field strain measurement method can quantitatively monitor the evolution of the displacement and strain fields at the marking point and surface simultaneously, thereby overcoming the limitations of traditional empirical and qualitative rupture processes. During monitoring, the AE focuses on the internal rupture of the specimen and the DIC focuses on the surface deformation. These complement each other and reflect the rupture process more comprehensively.

In the development of mineral resources and engineering construction in the western region, sandstone is one of the main engineering geological aquifers, and the freezing and thawing environment affects the mechanical and deformation characteristics of sandstone. In order to study the deterioration and damage characteristics of mechanical properties of loaded rocks under the influence of freeze-thaw environment, red fine sandstone in Shaanxi province was taken as the research object, and freeze-thaw cycle tests and uniaxial compression tests were carried out for 0, 5, 10, 20 and 30 times, and the stress-strain curve and mechanical characteristic parameters of the whole uniaxial compression process of frozen-thawed sandstone were obtained. The mechanical characteristic parameters of frozen-thawed rocks were analyzed, and the deterioration model of rock mechanical properties under freeze-thaw environment was established. Based on the influence of freeze-thaw environment on rock damage, considering the characteristics of rock compaction stage in deformation stage, a modified statistical damage constitutive model considering compaction stage is established. The results show that with the increase of freeze-thaw cycles, the proportion of rock compaction stage is increasing, and the peak value should also increase gradually. Brittle failure occurs in the first 30 freeze-thaw cycles, and the brittleness of rock is obviously weakened after 30 freeze-thaw cycles, and the strain softening stage is obvious. The loss rate of mechanical characteristic parameters increased rapidly in the first 10 times of freeze-thaw cycle, and then slowed down obviously. After 30 freeze-thaw cycles, the peak strength loss rate is 47.27% and the elastic modulus loss rate is 60.35%. Among them, the loss rate of mechanical characteristic parameters increases linearly with the number of freeze-thaw cycles, and the mechanical properties of rocks decrease exponentially after freeze-thaw. The peak strength and elastic modulus of rocks under freeze-thaw environment can be accurately predicted by using the pore characteristics of rocks under freeze-thaw environment. The modified statistical damage constitutive model considering the compaction stage has a higher fitting degree with the test curve, and the modified theoretical model can provide reference for the deterioration of mechanical properties and damage prediction of frozen-thawed rocks.

Abstract The mechanical properties of a coal–rock body were examined through uniaxial compression tests, and the rupture process of the coal–rock body was monitored in real time using a combined acoustic emission (AE) monitoring system and a digital image correlation (DIC) full-field strain measurement system. From a comparison of the mechanical properties of coal and sandstone, clear differences are apparent regarding the uniaxial compressive strength, deformation characteristics, and damage mode; the brittle failure characteristics of the coal samples are also more evident. The change in AE energy reflects the accumulation and release of elastic energy during the rupture process, and the evolution of AE localization points under different stress levels can effectively reflect rupture propagation. Further, the DIC full-field strain measurement method can quantitatively monitor the evolution of the displacement and strain fields at the marking point and surface simultaneously, thereby overcoming the limitations of traditional empirical and qualitative rupture processes. During monitoring, the AE focuses on the internal rupture of the specimen and the DIC focuses on the surface deformation. These complement each other and reflect the rupture process more comprehensively.

采用数值分析法对云县至凤庆高速公路随带开挖工程所不同埋深岩层竖向位移变化情况进行了解,通过归纳围岩土体变形规律提出具体的应对之策.结果发现:同一监测断面内,围岩变形峰值出现在隧道拱顶中心轴线上方,围岩沉降大小与其同隧道拱顶的距离呈反相关关系,变形曲线呈W型;岩层变形量与拱顶的距离呈正相关关系,岩层变形量在拱顶上方70 m之后越来越小,表现为直线.

以楚雄段施工6标倒虹吸交通洞施工支洞区间隧道工程为背景,提出隧道爆破振动现场监测试验的可行性研究方案.通过现场试验对爆破振动速度和震率变化规律进行研究.详细分析了现场试验爆破点距离监测点距离处最大振动速度变化规律,发现爆破振动速度和震率符合M.A.萨道夫斯基地振动最大速度经验公式.

以晋城矿区厚覆盖层下开采引起的地表移动为研究对象,在采煤工作面上方地表走向和倾向布置混凝土灌注测点,采用GPS快速静态定位测试与动态测试相结合的方法,对工作面回采后地表移动量进行了监测.采用MATLAB软件对地表移动数据进行分析,运用概率积分法得到工作面上方走向和倾向地表下沉曲线.结果表明,该区域内走向下沉最大值达4.692 m,倾向最大下沉值为4.043 m,充分采动后埋深采高之比与下沉量呈负相关关系;概率积分法对该区域内地表沉降预测较为准确,走向平均相对误差为4.7％;该区域地表下沉活跃期约130 d.