Slope deformation partitioning and monitoring points optimization based on cluster analysis

The scientific and fair positioning of monitoring locations for surface displacement on slopes is a prerequisite for early warning and forecasting.However,there is no specific provision on how to effectively determine the number and location of monitoring points according to the actual deformation characteristics of the slope.There are still some defects in the layout of monitoring points.To this end,based on displacement data series and spatial location information of surface displacement monitoring points,by combining displacement series correlation and spatial distance influence factors,a spatial deformation correlation calculation model of slope based on clustering analysis was proposed to calculate the correlation between different monitoring points,based on which the deformation area of the slope was divided.The redundant monitoring points in each partition were eliminated based on the partition's outcome,and the overall optimal arrangement of slope monitoring points was then achieved.This method scientifically addresses the issues of slope deformation zoning and data gathering overlap.It not only eliminates human subjectivity from slope deformation zoning but also increases the efficiency and accuracy of slope monitoring.In order to verify the effectiveness of the method,a sand-mudstone interbedded CounterTilt excavation slope in the Chongqing city of China was used as the research object.Twenty-four monitoring points deployed on this slope were monitored for surface displacement for 13 months.The spatial location of the monitoring points was discussed.The results show that the proposed method of slope deformation zoning and the optimized placement of monitoring points are feasible.

Investigation on long-term progressive deformation of engineering slope based on comprehensive monitoring

A landslide always results from a progressive process of slope deformation. In recent years, an increasing number of slope instabilities have occurred with regard to human engineering activities such as hydropower or traffic construction in mountainous area, which cause even greater casualties and economic loss compared with the natural hazards. The development of such earth surface process may hold long period with mechanisms still not fully understood. Using monitoring technology is an effective and intuitive approach to assist analyzing the slope deformation process and their driving factors. This study presents an engineering slope excavated during the construction of Changheba Hydropower Station, which is located in the upper reaches of Dadu River, Sichuan Province, southwest China. The engineering slope experienced and featured a five-year continuous deformation which caused continuous high risks to the engineering activities. We conducted in-depth analysis for such a long-term deformation process based on ground and subsurface monitoring data, collected successive data with a series of monitoring equipment such as automated total station, borehole inclinometers and other auxiliary apparatus, and identified the deformation process based on the comprehensive analysis of monitoring data as well as field investigation. After analyzing the effects of engineering activities and natural factors on the continuous deformation, we found that the overburden strata provided deformable mass while the excavation-produced steep terrain initiated the slope deformation in limit equilibrium state over a long period of time;afterwards, the intense rainwater accelerated slope deformation in the rainy season.

Wireless remote spatiotemporal monitoring of high-fill foundation deformation

The spatial and temporal deformation patterns and deformation control indicators of highfill foundations directly affect the design,construction and operational safety of high-fill projects.In situ monitoring can comprehensively reflect the deformation of high-fill during and after construction.In this paper,we have first designed and installed an integrated wireless remote monitoring system for high-fill to achieve real-time dynamic monitoring of settlement,pore water pressure and soil pressure of the fill foundation.Based on the monitoring results of nearly one year of the construction period and two years after construction,it was found that the deformation amount and deformation rate of the high-fill foundation showed a non-linear growth relationship with the filling rate and filling height.The settlement deformation of the high-fill foundation during the loading period was mainly dominated by the original foundation soil,accounting for 54.4%of the total settlement on average;the settlement deformation during the post-construction period was mainly dominated by the filling body,accounting for 77.04%of the total settlement on average,and the settlement deformation during the post-construction period mainly occurred in the first year after construction.The analysis of the deformation mechanism suggests that the deformation of the filling body is dominated by exhaust consolidation during the loading period and drainage consolidation during the post-construction period;the deformation of the original foundation soil is dominated by drainage consolidation during the loading period and drainage consolidation develops slowly during the post-construction period.It is recommended that the original foundation should be reinforced before the large area filling construction,and that the filling rate should be strictly controlled during construction.The research results can provide a scientific basis for deformation calculation and stability assessment of high-fill foundations.

Research on monitoring system for slope deformation

The monitoring system for slope deformation which bases on Leica （TCA series） was researched and developed. This system consists of electronic total stations, high precision thermometer, digital barometer, photoelectric frequency adjustor and other related instruments and data collection and processing software. The system can monitor a series of targets automatically to obtain accurate data of distance at predetermined time, besides, it can timely display targets＇ coordinates and deformation value, velocity, etc. in graph as well. To compare of the results of different monitoring time, we can find the problems of mine slope deformation rapidly and accurately.

Short-term displacement prediction for newly established monitoring slopes based on transfer learning

This study makes a significant progress in addressing the challenges of short-term slope displacement prediction in the Universal Landslide Monitoring Program,an unprecedented disaster mitigation program in China,where lots of newly established monitoring slopes lack sufficient historical deformation data,making it difficult to extract deformation patterns and provide effective predictions which plays a crucial role in the early warning and forecasting of landslide hazards.A slope displacement prediction method based on transfer learning is therefore proposed.Initially,the method transfers the deformation patterns learned from slopes with relatively rich deformation data by a pre-trained model based on a multi-slope integrated dataset to newly established monitoring slopes with limited or even no useful data,thus enabling rapid and efficient predictions for these slopes.Subsequently,as time goes on and monitoring data accumulates,fine-tuning of the pre-trained model for individual slopes can further improve prediction accuracy,enabling continuous optimization of prediction results.A case study indicates that,after being trained on a multi-slope integrated dataset,the TCN-Transformer model can efficiently serve as a pretrained model for displacement prediction at newly established monitoring slopes.The three-day average RMSE is significantly reduced by 34.6%compared to models trained only on individual slope data,and it also successfully predicts the majority of deformation peaks.The fine-tuned model based on accumulated data on the target newly established monitoring slope further reduced the three-day RMSE by 37.2%,demonstrating a considerable predictive accuracy.In conclusion,taking advantage of transfer learning,the proposed slope displacement prediction method effectively utilizes the available data,which enables the rapid deployment and continual refinement of displacement predictions on newly established monitoring slopes.

Mechanism of rock deformation and failure and monitoring analysis in water-rich soft rock roadway of western China

Aiming to get the strata behavior and stability rules of surrounding rock of the main return airway of Yushujing Coal Mine, convergence deformation of two sides and force of U-shaped steel yieldable support and bolt were monitored, and deformation of surrounding rock and mechanical characteristics of support structure were timely obtained to guide the informa- tion construction and optimize supporting parameters in water-rich soft rock roadway. The field monitoring results indicate the following. （1） Convergence displacement of rock surface increases with time continuity and shows surrounding rock＇s intense theological behavior. The original support scheme cannot control the large deformation and strongly theological behavior; （2） Without backfilling, the U-shaped steel support begins to bear load after erecting for 4-7 days and increases rapidly in the first 30 days. The U-shaped steel support at the right shoulder and top of roadway bears a larger force and the left side and shoulder bears a smaller force; （3） The stress of bolt increasing over time and at the right shoulder of roadway has larger growth and value. The mechanism of rock deformation and the failure and strata behavior in water-rich soft rock roadway are revealed based on the results of the measured relaxation zone of surrounding rock, measured stresses, and the rock mechanics tests.

Excavation compensation theory and supplementary technology system for large deformation disasters

Given the challenges in managing large deformation disasters in energy engineering,traffic tunnel engineering,and slope engineering,the excavation compensation theory has been proposed for large deformation disasters and the supplementary technology system is developed accordingly.This theory is based on the concept that“all destructive behaviors in tunnel engineering originate from excavation.”This paper summarizes the development of the excavation compensation theory in five aspects:the“theory,”“equipment,”“technology,”the design method with large deformation mechanics,and engineering applications.First,the calculation method for compensation force has been developed based on this theory,and a comprehensive large deformation disaster control theory system is formed.Second,a negative Poisson's ratio anchor cable with high preload,large deformation,and super energy absorption characteristics has been independently developed and applied to large deformation disaster control.An intelligent tunnel monitoring and early warning cloud platform system are established for remote monitoring and early warning system of Newton force in landslide geological hazards.Third,the double gradient advance grouting technology,the two-dimensional blasting technology,and the integrated Newton force monitoring--early warning--control technology are developed for different engineering environments.Finally,some applications of this theory in China's energy,traffic tunnels,landslide,and other field projects have been analyzed,which successfully demonstrates the capability of this theory in large deformation disaster control.

A generalized multi-field coupling approach and its application to stability and deformation control of a high slope

Human activities, such as blasting excavation, bolting, grouting and impounding of reservoirs, will lead to disturbances to rock masses and variations in their structural features and material properties. These engineering disturbances are important factors that would alter the natural evolutionary processes or change the multi-field interactions in the rock masses from their initial equilibrium states. The concept of generalized multi-field couplings was proposed by placing particular emphasis on the role of engineering disturbances in traditional multi-field couplings in rock masses. A mathematical model was then developed, in which the effects of engineering disturbances on the coupling-processes were described with changes in boundary conditions and evolutions in thermo-hydro-mechanical （THM） properties of the rocks. A parameter, d, which is similar to damage variables but has a broader physical meaning, was conceptually introduced to represent the degree of engineering disturbances and the couplings among the material properties. The effects of blasting excavation, bolting and grouting in rock engineering were illustrated with various field observations or theoretical results, on which the degree of disturbances and the variations in elastic moduli and permeabilities were particularly focused. The influences of excavation and groundwater drainage on the seepage flow and stability of the slopes were demonstrated with numerical simulations. The proposed approach was further employed to investigate the coupled hydro-mechanical responses of a high rock slope to excavation, bolting and impounding of the reservoir in the dam left abutment of Jinping I hydropower station. The impacts of engineering disturbances on the deformation and stability of the slope during construction and operation were demonstrated.

3D deformation effect and optimal excavated design of surface mine

The three-dimensional （3D） deformation effect of the slope engineering under the step-by-step excavation for the Antaibao surface mine was analyzed using the FLAC^3D technique. An optimal excavated scheme with a relatively steeper slope angle of 47° instead of 30° was successfully implemented at the west wall in the geological section 73200 of the mine area, where the 3D effect of the nonlinear large deformation of the slope was taken into account. Based on the above research conclusion, put forward the countermeasures of shortening mining length, excavating by different regions, timely foot backfilling to protect the excavated slope, and monitoring and feedback adjustment by studying the nonlinear effect. The results show that these countermeasures are effective in controlling maximum deformation and increasing the stability of the slope.

Deformation features and failure mechanism of steep rock slope under the mining activities and rainfall

Underground mining activities and rainfall have potential important influence on the initiation and reactivation of the slope deformations,especially on the steep rock slope. In this paper,using the discrete element method(UDEC),numerical simulation was carried out to investigate deformation features and the failure mechanism of the steep rock slope under mining activities and rainfall. A steep rock slope numerical model was created based on a case study at the Wulong area in Chongqing city,China. Mechanical parameters of the rock mass have been determined by situ measurements and laboratory measurements. A preliminary site monitoring system has been realized,aiming at getting structure movements and stresses of unstablerock masses at the most significant discontinuities. According to the numerical model calibrated based on the monitoring data,four types of operation conditions are designed to reveal the effect of mining excavation and extreme rainfall on the deformation of the steep rock slope.

Large-Scale Test Model of the Progressive Deformation and Failure of Cracked Soil Slopes

A large-scale test bed(LWH=6 m×3 m×2.8 m)instrumented with various sensors is used to examine the effects of rainfall infiltration and evaporation on the deformation and failure of cracked soil slopes,taking the Anhui area along the Yangtze River as a field example.The results indicate that(1)during rainfall,the soil around the shallow shrinkage fissures attains transient saturation,and the attendant decrease of matric suction is the primary cause of the shallow slope failure;(2)slope deformation continues during post-rainfall evaporation;(3)if a period of evaporation is followed by heavy rainfall,soil creep is concentrated near the deepest cracks,and two zones of steep gradients in pore pressure form at the crest and toe of the slope.Finally,a saturated zone forms near each crack base and gradually enlarges,eventually forming a continuous saturated layer that induces the slope instability or failure.

大凉山背斜核部区隧道初支大变形机理与控制

针对大凉山2号公路隧道穿越高地应力背斜核心区域,隧道易发生初支大变形、坍塌、钢架扭曲等问题,通过现场监控量测、围岩岩性实验、理论分析、数值模拟分析和围岩接触压力监测等综合分析,研究了大凉山2号隧道背斜核部大变形成因机理。研究表明:背斜核部玄武岩单轴抗压强度为23.31 MPa,凝灰质泥岩遇水具有一定膨胀性,给围岩变形创造了条件。由于岩层岩性不同,开挖后洞周玄武岩呈独立受弯剪梁状态。相对无水条件下,受地下水补给影响,围岩塑性区面积增加,拱腰部位较为明显。加固前,拱顶沉降量最大达470 mm,拱腰最大收敛值为844 mm,围岩接触压力为523.47 kPa。采用双层小导管+中台阶临时支撑+边墙临时支撑的“主动适应+强支撑”的综合处置方式,隧道拱顶变形减少87.6%,水平收敛变形减少95%,围岩接触压力最大值降至128 kPa,隧道变形得到有效控制。

基于倾角反演的隧道断面变形全方位监测方法

倾角传感器具有体积小、使用方便、测量连续等优点,在隧道变形监测领域有着巨大应用潜力,然而,现有基于倾角传感器的监测方法往往只能得到特定监测点的变形,在测量隧道断面整体变形方面还存在明显不足。为此,提出一种新的基于监测点倾角的隧道断面变形全方位监测方法。基于隧道断面曲线的形状特征,构造隧道分段变形插值函数,根据极坐标下隧道倾角与极径的关系,采用分段解析方法提出隧道倾角-变形数学模型,进一步通过协同变形假定,修正隧道测点极角,得到隧道倾角-变形算法;接着,建立隧道三维数值模型,通过均布荷载、对称非均布荷载和非对称荷载3种典型工况,采用误差分析方法分别研究算法的适用性;最后,通过室内试验进一步验证算法在实际应用中的准确性。研究结果表明:对于铁路隧道典型三心圆断面,推导的倾角-变形算法在均布荷载、对称非均布荷载和非对称荷载这3种典型工况下均具有良好的适应性,变形最大绝对误差均小于1 mm,平均相对误差均小于7%;在室内模型试验中,拱顶沉降监测误差小于8%,水平收敛监测误差小于5%,证明了监测方法的准确性。

基于数值模拟和变形监测的副井稳定性评价

急倾斜矿体开采时一般将副井布置在矿体下盘不远处,以致副井附近矿体开采可能诱发副井井壁应力集中或损坏。为此,以湖北三鑫为例,利用FLAC3D仿真软件,探究沿走向或垂直走向布置采场引起的副井围岩应力、位移变化,并采用应变计、位移计监测井壁应力与位移变化,评价副井稳定性。结果表明:沿矿体走向布置采场对采场围岩、悬空底柱及开采段副井井壁的稳定都极为不利,沿走向或大宽度垂直走向布置采场都不会引起地表及开采标高段附近的副井发生明显位移,但都会引起井口以下约250 m内的井壁因变形而发生应力集中;必须垂直走向布置采场并缩小采场宽度;采取4 m×4 m进路上向胶结充填二步骤采矿后,除岩土分界面附近井壁偶尔因开快车而造成连续2次垂直位移、应力差分别超1.2 mm、1.4 MPa外,其他监测值变化基本可忽略;地表基岩沉降观测表明各点沉降值变化一般不超过3 mm。

公路路基变形破坏及其测试技术研究进展与展望

路基变形是公路病害的主要原因之一,其在公路建设、管理、运营、养护过程中带来的隐患日益凸显。目前以遥感测绘、地球物理探测、多传感器为代表性的相关技术,在路基变形测试中发挥了重要作用。为研究道路工程领域动态和行业发展趋势,梳理近年来道路工程领域理论、方法、技术及装备研究现状,阐述了公路路基变形的主要形式及影响因素,分析了路基变形测试技术类型及其优缺点,进一步讨论了对全周期智慧监测体系的认识及其发展趋势。构建路基变形监测体系是感知路基状态、路基稳定性评估和灾害预警的主要途径。随着人工智能和先进测试技术的快速进步,路基变形测试技术呈现出动态化、透明化、智慧化等新特点。加强公路测试基础理论、技术与装备的研发,形成基于立体空间的多手段路基健康监测体系是未来道路安全运维的重要发展方向。

基于光纤传感技术的工程监测应用研究

光纤传感技术作为当前热门技术之一,在工程监测领域有着许多重要应用。通过探讨光纤传感技术在工程形变监测中的应用案例,展示了其在工程监测领域的重要性。光纤传感技术利用光纤作为传感元件,可以实现对形变的连续、实时监测,并提供高精度的监测数据。通过布设应变光缆和温度补偿光缆,在合璧津高速公路K134段高架桥上进行了监测实验。结果表明,光纤传感技术能够准确评估结构的变形情况,并通过温度补偿算法消除了温度变化对数据的影响。通过几何方法计算沉降位移,可以实现对沉降位移的估算。

特高拱坝变形机理可解释性智能预测模型

针对传统“黑箱”模型可以预测却无法解释拱坝变形的缺陷,利用Shapley Additive Explanation(SHAP)理论对特高拱坝的机器学习变形预测模型进行解构分析,分析水压、温度、时效对特高拱坝不同部位径向水平位移的影响规律。构建特高拱坝变形监测数据的轻量梯度提升算法(Light Gradient Boosting Machine,LightGBM)黑箱预测模型,利用SHAP对存在多重共线性的因子进行剔除,再从整个因子集和单个样本两个角度分析不同影响因子对模型变形预测的贡献度;通过分析拉西瓦特高拱坝坝肩、坝基、拱冠等不同部位的径向水平位移与影响因子间的关系,发现时效因子对高程越高、越靠近拱冠位置的径向水平位移影响越大,温度因子主要影响靠近拱冠位置的径向水平位移,水压因子主要影响高程较高位置的径向水平位移,而坝基和深入坝肩岩体测点的径向水平位移几乎不受水位、温度的影响。解决了以往“黑箱”变形预测模型可视性差、内部机理不明的问题,根据可解释模型得到的相关规律可为特高拱坝的工作性态分析和运行管理提供借鉴。

露天矿无人机遥感边坡地表形变提取方法研究

针对当前露天矿边坡监测过程中存在的设备留有监测死角、点位布控缺乏依据、地质隐患解译困难、无人机(Unmanned Aerial Vehicle,UAV)影像点云重构复杂度高等问题,提出了一种基于无人机遥感的边坡地表形变提取方法。首先,通过分析UAV激光点云与影像特点构建点云序列;其次,利用融合尺度不变特征变换(Scale Invariant Feature Transform,SIFT)与圆柱形邻域搜索的改进迭代最近点(Iterative Closest Point,ICP)算法,实现点云序列的精准高效配准,提高边坡形变提取精度;最终,借助数字高程模型(Digital Elevation Model,DEM)叠加分析与可视化,精准定位边坡重点形变区域,直观提取边坡形变位置和大小,并结合正射影像图像特征进行形变区域分析与解译。以南芬露天矿为工程应用实例,研究表明:边坡形变模型标准偏差为0.032 m,对比全球定位系统-实时动态差分(Global Positioning System-Real Time Kinematic,GPS-RTK)实测形变值,形变中误差为0.012 m,能够快速实现大尺度复杂边坡地表扫描与形变提取,从而为地质灾害隐患分析、盲区边坡形变监测与地面监测设备科学布控提供技术支撑。

岩土工程表面变形监测应用技术现状分析与发展思考

本文从表面变形监测技术现状出发,阐述其技术发展历程,针对建(构)筑物、边(滑)坡、地基基础、地下工程等不同工程类型的特点,结合国家现行技术标准要求,分析当前表面变形监测方法的适用性、存在问题及可能的解决办法。分析认为:自动化监测代表当前表面变形监测发展的主流;面监测为下一阶段表面变形监测发展的重要方向;基于近景摄影测量的表面变形监测技术具有较好的发展前景。

圆弧式地基合成孔径雷达在边坡变形监测中的应用

边坡变形监测是防止滑坡、崩塌、泥石流等地质灾害的有效途径之一。圆弧式地基合成孔径雷达是一种非接触式的新型地表形变监测设备,具有高分辨率、高频率、高精度、全方位、全天候实时监测等优点,更能有效地满足边坡变形监测的全面性和连续性要求。为了验证该设备在边坡变形监测中的效果和精度,本文采用两种便携圆弧式地基合成孔径雷达系统进行测试。测试结果表明,两种设备均能快速、全面地获得整个边坡的形变情况,具有较高的分辨率和亚毫米级的监测精度,且能实时发出预警,是一种全面高效的边坡变形监测手段。