Objective As human engineering activities expanded into the Tibetan Plateau and its surrounding areas, slope instabilities—particularly large-scale landslides—in deeply incised valleys have occurred with increasing frequency, posing severe threats to major infrastructure projects and public safety. This study evaluates how regional tectonic activity controls slope stability and outlines key challenges, insights, and strategic recommendations for slope engineering planning and construction in these deeply incised valleys. Methods Based on an overview of the tectonic activity characteristics across the Tibetan Plateau, the controlling influence of tectonic activity on slope stability was systematically analyzed. Problems encountered in slope engineering planning were identified, leading to practical engineering recommendations and strategic directions for future research. Results Tectonic activity exhibits strong spatial consistency and temporal synchronicity with slope instability across the plateau. Tectonic processes provide the essential structural and geomorphic boundaries, material sources, dynamic conditions, and triggering factors for slope failures. Key challenges include the dominant control of regional tectonic stress on valley slope stability, the need to re-evaluate reverse slope stability in deeply incised valleys, and the required paradigm shift regarding the horizontal cover depth for mountain-adjacent underground works. Analysis suggests that slope engineering should prioritize south-, west-, and southwest-facing slopes while avoiding north-, northeast-, and east-facing slopes. Furthermore, the deep-seated stability of consequent slopes is superior to that of reverse slopes, and underground structures along mountain slopes should be situated within the unperturbed in-situ stress zone. Conclusions Future research must focus on quantitative investigations into: (1) the morphological characteristics and failure mechanisms of deeply incised valleys; (2) the evolution of in-situ stress fields under rapid tectonic uplift; and (3) the spatial distribution of in-situ stress fields across the plateau. Significance The findings provide critical theoretical guidelines and engineering references for slope design, infrastructure planning, and geohazard mitigation on the Tibetan Plateau.

Objective The stability of underground chambers such as mine tunnels and transportation tunnels is closely related to the stress environment of the surrounding rock mass and the geological conditions of the area. Analyzing the relationship between deep-seated stress and factors such as the orientation and shape of underground chambers can help to proactively mitigate the risks associated with chamber excavation. Methods This study, set against the background of the rock burst accident on October 20th in the Longyun Coal Industry area in Shandong, reveals the current stress environment of the shallow crustal layers in western Shandong through in-situ stress measurement and monitoring work. Results According to the characteristics of the current ground stress field near the Longyun coal mining area, the study investigates the regional stress background that led to the rock burst accident and proposes corresponding prevention and control suggestions from the perspective of ground stress. The results indicate that the magnitude of the principal stress generally increases linearly with depth within the measurement range, with the maximum horizontal principal stress ranging from 3.48 to 20.76 MPa and a gradient of 0.0182 MPa/m with increasing depth, while the minimum horizontal principal stress ranges from 3.44 to 14.95 MPa with a gradient of 0.0130 MPa/m. The maximum horizontal principal stress azimuth in the area ranges from NE 43°to 89°, with an average azimuth of NE 75°. The tectonic action in the shallow crust is mainly horizontal, but with increasing depth, they gradually transition to vertical. Conclusion The triggering mechanism of the rock burst accident in the Longyun Coal Industry area on 20th October is primarily attributed to the vertical stress exceeding the horizontal principal stress, indicating a current extensional stress environment, especially when the tunnel orientation is parallel to the direction of maximum horizontal principal stress. It is suggested that the angle between the tunnel axis and the direction of maximum horizontal principal stress in the Longyun Coal Industry area should be between 60° and 90°, and that the tunnel roof can be designed as an arch-shaped roof to ensure the stability of the tunnel rock mass.

构造活跃区大量工程实例表明,地应力是影响深埋隧道稳定性的重要因素之一.应用三维应力场有限元数值模拟探讨了青藏高原及邻区最大水平主应力方向和隧道轴向夹角φ与侧压力系数KH耦合变化对深埋隧道应变能分布及岩爆倾向的影响.对不同地应力条件下深埋隧道围岩应变能密度分布特征进行了分析,并通过数值分析初步厘定最大水平主应力方向和隧道轴向夹角、侧压力系数与隧道不同关键位置应变能密度的多元回归方程.研究结果表明:最大水平主应力方向和隧道轴向夹角φ=45.左右时,隧道夹角变化对岩爆倾向性影响最大;最大水平主水平应力方向和隧道轴向垂直时,KH变化对围岩应变能密度影响最显著;当最大水平主应力方向和隧道轴向平行时,KH变化对围岩应变能密度影响最小.所厘定的多元回归方程已通过多条青藏高原及邻区典型深埋隧道验证,可用于快速评估夹角和侧压力系数对隧道稳定性的影响,高效服务隧道规划设计.

Recently, water injection-induced earthquakes caused by faulting instability have become a prominent geological safety issue for safely exploiting deep geothermal resources. This study investigates whether the future large-scale development of deep geothermal resources in the Gaoyang uplift will destabilize buried faults. There has a great amount of karst thermal reservoir in the Gaoyang low uplift, Hebei province. To find out whether the large-scale deep geothermal exploitation in the future will induce faults distributed in and around Gaoyang geothermal reservoir to become unstable, firstly, we calculate the initial stable state of the main buried faults based on Mohr-Coulomb criteria using the comprehensive in-situ stress field of North China; then, under Hsieh and Bredehoeft hydrological model, we calculate the possible excess pore pressure caused by water injection for 10～40 years at representative geothermal wells; subsequently, combing this perturbation with the initial stable state, we obtain the fault slip potential of the main buried faults from 2022 to 2062 based on a probabilistic approach; ultimately, we discuss the impact on the changes of fault slip potential due to varying angles between the maximum horizontal principal stress and the fault orientation. The main conclusions of this work can be drawn as follows. With the injection rate of 170 m~3/h, the maximum excess pore pressure caused by a single geothermal well does not surpass 11 MPa, and it obeys a power decrease distribution with increasing distance from the center of the injection well; its influence scope is no more than 8 km. Continuous water injection strongly changes the stability of those buried faults distributed 2 km within the geothermal wells, and fault-slip potentials of some segmental faults even exceed 85%, corresponding to high unstable risk. Under 50 years of water injection at an injection well, the fault-slip potential of faults with different strikes within 2 km from the injection well increases rapidly with the declining angle among its orientation and the regional maximum horizontal principal stress. This paper’s study methodology and associated findings can offer geoscientific justification for the safe exploration and exploitation of deep geothermal resources domestically and internationally. This study can provide a method reference for the location of injection wells and the selection of faults in different orientations in geothermal fields at home and abroad, thus promoting the safe and efficient development and utilization of geothermal resources.

The concentration, complexity, and significant anisotropy of in-situ stress make it a pressing and challenging issue in engineering geology safety in strong tectonic activity areas. This paper firstly analyzes the application and existing problems of in-situ stress measurement in deep-buried underground engineering in strong tectonic activity areas. Then, it focuses on the application method, technology, and roles of real-time in-situ stress monitoring in deep underground engineering within tectonically active regions. Finally, it discusses the problems that need to be considered in the application of in-situ stress measurement and real-time monitoring. The results show that in the strong tectonic activity area, relying solely on limited deep hole in-situ stress measurements to determine overall stress design parameters for deep underground engineering is inadequate. A comprehensive study of the three-dimensional in-situ stress field is necessary to reveal its spatial distribution characteristics. Different in-situ stress design parameters should be used for different positions of the deep-buried underground project to avoid engineering waste or engineering damages caused by large or small in-situ stress design parameters. In the strong tectonic activity area, the disk core density is inversely proportional to the measured magnitude of the in-situ stress, and the depth range that has yet to form in the cake-shaped core often has the highest in-situ stress and the most concentrated stress, and the deep underground engineering should avoid this depth range. While a major earthquake or major engineering geological problem occurs, real-time monitoring of in-situ stress can dynamically reveal the relative change trend and evolution process of the in-situ stress magnitude of a specific structural site. It can calculate the absolute value of the in-situ stress state in different time domains during the real-time monitoring period without carrying out new absolute in-situ stress measurements. Regional crust stability and deep-buried engineering geological safety risks can be quickly evaluated, and quantitative in-situ stress design parameters and the stress-strain reserved threshold for preventing deformation and breaking can be provided for the damage repair of deep-buried engineering and the risk of fault activity can also be assessed. The research results will offer geological security for the planning, construction, and safe operation and maintenance of major projects in strong tectonic activity areas.

混合源面波与三分量频率谐振勘探方法是近年来兴起的一套新型城市地球物理探测技术.以黄庄-高丽营断裂为例,采用主动源多道瞬态面波、混合源多道瞬态面波勘探和三分量地震频率谐振勘探方法进行实验研究.研究结果表明,主动源面波勘探可清晰展示地表以下15 m的地质构造;混合源多道瞬态面波,综合主动源信号和被动源(噪声)优势,增加其探测深度;三分量地震频谱谐振H/V谱比结果可清晰反映地质构造,并与主动源面波勘探方法探测的10～15 m深度的低速异常带特征相似;三种方法相互结合应用,既提供了多种数据源,也提高了数据解译的精度与可信度.

城市地质条件适宜性评价是支撑城市规划建设区控制性详细规划编制和工程建设前期开展的专项地质调查工作.北京地区调查评价内容包括地形地貌、水文地质、工程地质等3项基础地质条件,活动断裂、地面沉降、地裂缝、崩塌、滑坡、泥石流、采空塌陷、岩溶塌陷、砂土液化、地下水污染、土壤污染等11项地质环境要素,地下水资源、深层地热资源、浅层地热能等3项地质资源要素.在现有标准基础上,结合北京地区城市地质工作实践,新建了1:10000和1:2000精度城市地质条件调查方法体系,并设定了工作布置参数;构建了城市地质条件评价指标体系,包括61项评价指标,其中新增指标20项、修订指标31项、引用现有标准指标10项.

In order to ascertain the impact of the Tohoku-Oki 3.11 M9.0 earthquake on the stability of the faults in the Tangshan seismic region, we investigated the adjustment of the in situ stress field of the seismic region after this earthquake based on in situ stress monitoring data. Then, according to the Mohr-Coulomb failure criteria and Byerlee’s law, we used the FSP v.1.0 software package to calculate the fault slip potential (FSP) of the main faults in the seismic region at each adjustment stage of the in situ stress field, and to study the risk of fault activity. The research results show that 1) after the Tohoku-Oki 3.11 M9.0 earthquake, the tectonic environment of the Beijing Plain area changed rapidly from nearly EW extrusion to nearly EW extension, and this state was maintained until June 2012. After this, it began to gradually adjust to the state present before the earthquake. As of September 2019, at the depth of 100m, the maximum horizontal principal stress value in Tangshan seismic region was 7.61–7.81MPa, the minimum horizontal principal stress value was 5.30–5.50MPa, and the maximum horizontal principal stress orientation was N55.1°–59.5°E. (2) Before the Tohoku-Oki 3.11 M9.0 earthquake, the stress accumulation level of the main faults in the seismic region was relatively high with the FSP values of 30–60%. After this earthquake, the stress accumulation level of each fault continued to decrease, as of May 2013, the FSP values were mainly concentrated at 10–35%. Then, the stress accumulation level of major faults in the seismic region began to gradually increase. As of September 2019, the FSP values were mainly concentrated at 23–37%, and the stress accumulation level was still lower than the pre-earthquake state. 3) The fault activity in the central and northern parts of the seismic region was the strongest, followed by the southern part and western part, and the fault activity in the eastern part was the weakest.

京津冀协同发展区是中国东部规划的战略开发区之一,也是华北地区主要的活动构造区,新构造活动强烈,活动断裂发育,地震频发,具有潜在的地质安全隐患问题.基于张家口地区、雄安新区及邻区、北京及关键构造部位调查研究结果,结合已有研究成果,系统分析了京津冀协同发展区主要活动断裂几何学、运动学和动力学特征及其工程地质、地质灾害特征,采用ArcGIS平台的空间分析功能,初步完成了京津冀协同发展区地壳稳定性评价.研究结果表明,京津冀协同发展区发育邢台-河间-唐山、石家庄-通州NNE向构造带和张家口-渤海NWW向区域性活动构造带,其中全新世活动断裂11条,晚更新世活动断裂16条,第四纪断裂23条;冀北及冀东南地区现今构造应力场最大水平主应力方向为近EW向,而太行山东缘南段为NNE向,北段为NW向;NNE向活动断裂带总体表现为顺时针扭动正断活动,倾向SE,NWW向活动断裂带晚更新世以来具有明显的活动性,整体表现为反时针扭动正断活动,倾向SW.京津冀协同发展区地壳稳定性总体较好,不稳定区及次不稳定区主要分布在邢台、唐山、延怀盆地和全新世活动断裂带内,利于重要城镇和重大工程规划建设.研究成果将为京津冀协同发展区宏观发展战略提供地质支撑.

李思庄滑坡为河北省顺平县境内潜在危险性最大的一残坡积堆积层滑坡,近年由于削坡建房,滑坡稳定性降低,极端降雨条件下存在复活可能.在野外调查确定滑坡结构特征的基础上,采用改进Mein-Larson降雨入渗模型分析不同降雨强度及持时对李思庄滑坡安全系数影响,运用有限差分软件FLAC3D计算分析该滑坡在天然和极端降雨工况下的稳定状态.研究结果表明:天然状态下,边坡潜在滑移面为基岩与残坡积层分界面,边坡安全系数为1.18,未发生失稳破坏;随降雨历时增加,潜在滑移面由基岩与残坡积层分界面转移到湿润峰面,当湿润峰达到基岩与残坡积层分界面,边坡安全系数为0.83,属不稳定状态.并对李思庄滑坡初步提出设置挡土墙和截排水沟的治理建议.

城市地下空间资源开发利用受到多种地质条件的综合影响,在现有技术条件下进行开发、利用以及运营时不可避免产生一定风险,为规避风险,要对地下空间资源开发利用的适宜性开展评价.本文以地下空间资源利用地质适宜性为评价对象,在北京市地下空间资源调查评价研究成果的基础上,建立了基于基础条件和约束条件相结合的地下空间资源开发利用地质适宜性评价指标体系,确定了各因子指标量化取值标准,建立了综合评价模型,划分了3个评价等级,通过模糊数学法和层次分析法,对北京市某地区地下空间资源开发利用地质适宜性进行了综合评价,取得了高度符合地质条件的优良成果.

城市地质资源环境承载力要素监测是城市发展中后期的重要基础性工作.监测体系建设的目标是全面掌握地质要素变化规律,为城市发展安全提供保证.该体系建设的总体思路是基础坚实、问题明确、平面分区、纵向分层、立体成网、全面采集、可靠传输、云端存储、抓住奇点、把握关联、构建模型、预测趋势、多级服务、有效应用.该体系的基础是数据采集系统,核心是分析系统,关键是应用系统.该体系的建设运行,可有效地提高城市地质安全保证水平.本文以北京市为例介绍了地质资源环境监测体系建设的实践.

地下空间资源探测是科学合理开发利用地下空间资源的基本前提,国内各大城市相继开展了地下空间资源调查评价工作,但对地下空间资源探测方法尚未开展系统梳理.在北京城市地下空间资源调查评价工作的基础上,对地下空间资源开发利用2个阶段,即建成区和待建区地下空间资源探测对象和探测方法分别做了阐述,指出建成区的探测对象是已开发利用的地下空间资源,可以采用遥感技术解译建筑物高度,利用建筑物竖向影响深度推算已利用开发地下空间,利用物探手段(电法、磁法、重力、地震)较精确地圈定已开发利用空间;对于待建区,调查对象主要是影响地下空间资源开发利用的地质条件,可以通过相应的地质工作开展调查.最后列举了应用实例,以期为城市地下空间资源探测工作起到借鉴作用.

城市区域地质条件适宜性评价,是指为了满足城市布局选址、规划建设、安全运行、转型升级对地质资源和地质环境的需求,特别是对定量化地质数据的需求而开展的工作,主要包括保障城市发展的地质资源和制约城市建设发展的地质环境问题.目前我国已颁布的国家、地方、行业标准中,对各项地质要素的评价以定性评价居多,指标定量化程度较低,而且部分评价指标不能全面反映评价对象演化趋势.本文在大量城市地质工作基础上,初步建立了一套城市区域地质条件适宜性评价定量化指标体系.本次工作一是将评价指标体系中不够完善的部分新设置了定量化指标,二是将部分指标评价由定性转为定量,三是修订了部分定量化指标的定量分级标准,旨在使地质成果满足城市发展需求,提高地质工作基础性支撑能力.

本文在系统研究国内外城市地质学理论研究与工作实践基础上,系统分析并拓展了城市地质学的内涵与外延;根据城市可持续发展的需求,提出了保证城市不同发展阶段地质安全是城市地质学理论研究的根本任务和永恒主题;明确提出了城市地质学研究的三个科学问题,即城市选址安全底限问题、城市发展规模上限问题、城市发展可持续性问题;由此构建了区域地质条件适宜性评价、地质资源环境承载力评价、城市地质作用研究,三方面的城市地质学理论体系.

Terrace is developed in Dashi River valley. It is mainly bed rock seated terrace. The first to fourth terraces are relatively well developed from Chenjiatai to Hongmeichang in lower reaches. Only one terrace is seen in upstream Zhuanghutai Village. The sediments are mainly gravels and sands in upstream reaches. They are sands and clays in lower reaches. The dating of fourth terrace in Hongmeichang Village yielded an age of 567±56ka, suggesting that the Dashi River was formed in Mid-Pleistocene. The four terrac?es were formed by uplift of New Tectonic Movement. The longitudinal river slope is 7.71‰from the river mouth of Xinkaikou Vil?lage to Longmentai Village in upstream reaches. Since 600ka, the Hill in Dashi River valley has been uplifted by 0.96mm/a.

本文选取北京平原区3条重要的控盆活动断裂,北西向的南口—孙河断裂,北东向黄庄—高丽营断裂和顺义断裂,对其第四纪以来的活动性进行深入研究.研究表明,目标断裂活动性第四纪以来均表现为较强—弱—强—较强的特点.在此基础上,对各条断裂活动性的共性特征进行总结,并以此表征本区新构造运动的特点.本区新生界以来构造运动显著,古近纪时期,北京平原形成"两隆一凹"的构造格局;新近纪时期,该构造格局解体,北京冲积平原初步形成;第四纪以来,新构造运动继承性发展,形成多个第四纪断陷盆地,诠释了构造与建造之间的密切关系.同时,对北京地区构造-气候耦合关系进行深入探讨,明确了构造-气候旋回具有0.4Ma的周期性,中更新世以后,0.1Ma的准周期开始成为主导周期的特点.该特点与青藏高原地区及中国大陆东部的新构造运动,具有较好的对应关系.

城市区域地质条件适宜性评价,是指为了满足城市布局选址、规划建设、安全运行、转型升级对地质资源及地质环境的需求,特别是对城市地质工作成果明确、定量化需求而开展的各项地质要素评价,主要包括保障城市发展的地质资源和制约城市建设发展的地质环境问题,对特定城市某些地质因素在选址布局、规划中起决定性作用.因此,城市区域地质条件适宜性评价工作,是一项不可或缺的基础性工作.本文拟通过大量城市地质工作实践,对国内外相关评价标准、评价方法进行深入分析研究,初步建立了一套地质要素进行定性、定量的评价方法,更好地服务于城市发展需求.

地下空间资源作为一种赋存于地质体内且受地质条件控制的资源,首先具有天然的自然属性;其次其开发利用受经济技术水平限制;并且其利用领域广泛,适用性与实用性强.正确认识地下空间的资源属性,对科学开发利用具有极其重要的理论价值和实际意义.

Active faults in urban have a potential damage to citizens, because they can induce not only earthquakes, but also damage pavements, utilities, homes, businesses, factories and other manmade structures because of the slow, secular and differential slippage. Consequently, the researches of detecting active faults are of great significance. This paper proposes a set of geophysical methods to detect active faults by an example in Beijing, including gravity, controlled source audio-frequency magnetotellurics(CSAMT), seismic reflection, DC resistivity and paleomagnetism (Natural remanent magnetization in rocks) to locate faults and discuss their activities. In proposed methods, gravity interpretation helps us obtain the distribution and characteristics of buried faults beneath the plain, the results of CSAMT, seismic reflection and DC resistivity reveal features and characteristics of faults from the deep to shallow part; paleomagnetism associated with radiocarbon dating help us analyze the fault slip rate; 3D seismic reflection interpretation shows the structure of two faults in the three-dimensional subsurface and the interaction of each other. Also, a few acquisition parameters, data processing methods and significant suggestions are mentioned.