基于岩体动力学演化模型的金属矿山塌陷区安全性Lyapunov指数评估方法

金属矿山采空区地面塌陷危险性预测过程中,仅利用灾害链进行程序评估预测,Lyapunov指数评估误差较大。考虑塌陷规模、特征、稳定性的数值模拟过程,设计一种基于岩体动力学演化模型的金属矿山塌陷区安全性Lyapunov指数评估方法。分析塌陷区冒落过程,结合顶板中拉应力和塌陷之间的关系,获取金属矿山塌陷区岩体弹性能等其他环境参数,利用岩体动力学演化模型进行数值模拟,直观定量地揭示出塌陷区内部动力学演化过程以及动力学特征;以塌陷区混沌时间序列为基础,得到重构相空间,根据光谱轨道的发散指数得到二维图像中的一条直线,利用最小二乘法逼近该直线,得到斜率具体值,即为目标最大Lyapunov指数。实验结果表明:该方法预测的两个监测点的安全性最大Lyapunov指数分别在61、62个月时超过0.3,监测点塌陷预测走势与实际的塌陷时间点更加吻合。降低了Lyapunov指数评估误差,为金属矿山塌陷区安全性分析提供新思路。

基于地表实测爆破振动的岩体动力学参数快速反演方法

岩体动力学参数的准确、快速获取对水利工程设计、施工及建设起着重要作用。尽管可通过现场原位试验、经验关系法等传统方法对其进行评估,但上述传统方法均存在耗时长、投资大等缺点,且难以准确快速的获取大尺度岩体动力学参数。本文通过分析地表实测爆破振动波形,识别出各测点P、S波初至到时,进一步给出各个测点区间内P、S波的平均传播速度,提出基于地表实测振动的岩石动力学参数预测方法。并以丰宁抽水蓄能电站为例,基于爆破试验实测振动数据反演的岩体动态模量约为北京勘测设计研究院推荐使用的静态模量值的2.2～2.9倍,动泊松比为静泊松比的0.9～0.975倍。提出的基于地表实测振动预测岩体动力学参数的方法为工程尺度下快速获取岩体动力学参数提供了一条新途径。

剧冲式高速岩质滑坡运动全过程动力学机制研究

剧冲式高速岩质滑坡运动全过程动力学机制研究是论证分析高陡斜坡岩体的破裂、变形、破坏、失稳与滑体的高速运行、碰撞解体及冲击成坝全过程的动力学规律。本文提出了工程地质条件→斜坡岩体力学性质→斜坡变形破坏机制→滑坡几何学、运动学、动力学模型→斜坡变形破坏及运动过程数值模拟仿真→高速岩质滑坡运动全过程动力学理论方程及公式→滑坡体（坝）超稳性综合分析与评价的研究途径和技术路线来解决这一问题。以川西青衣江上游宝兴河蜂桶寨水电站龙店子坝址区大板桥滑坡（坝）为例，在广泛、深入的现场调查和室内外岩土物理力学性质综合测试的基础上，对斜坡变形破坏及滑坡运动全过程的动力学机制进行了全面地、系统地研究。首先，研究了高陡斜坡所在的区域地质构造、区域构造应力场、现代地壳稳定性、区域地形地貌、水文地质及地质灾害群体发育特征等工程地质条件。其次，研究了斜坡岩体结构、斜坡岩体力学特性、斜坡变形破坏形式及机制，建立了斜坡变形破坏的地质力学模型。在深入研究滑坡发育形态、空间分区、结构特征；滑带土宏观结构、ＳＥＭ微观形貌综合特征、物质成分；滑坡土石体物理力学性质、本构模型及参数的基础上，建立了滑坡几何学、运动学、动力学模型。通过有限元反演分析，基于?

采动力学与岩层控制关键理论及工程应用

研究岩体采动力学响应和岩层控制技术对促进煤炭安全高效开采,保障能源稳定供给具有重要意义,是实现煤炭资源科学开采的理论基础。矿山岩体灾害(围岩变形、冲击地压等)频发,其形成一演化一发生全过程与采动力演化分布、岩层运动、开采扰动和能量演化密切相关。基于实用矿山压力控制理论,提出并阐述了采场岩层控制进展与控制准则,建立了定量分析的力学模型和设计方法,发展了针对性的岩体灾害控制技术,并创新研制了配套试验研究装备。采动力学与岩层控制理论将岩层控制分为采场岩层控制和巷道围岩控制;提出控制或利用采动岩层运动改变致灾条件,给出“给定变形”和“限定变形”准则;调控“3S”因素准则(围岩应力环境、围岩结构属性、围岩支护结构)改变围岩自稳能力。以岩体灾害控制为目标,提出了以“应力主控”为核心的释能主控技术;建立了岩体灾害控制大小原理和弱面判据(安全系数K、冲击危险性系数U);分别从采场岩层控制、地质软岩控制、工程软岩巷道控制及冲击地压控制四个方向进行了工程案例研究,相关研究成果在工程应用中得到了验证。

广东省建科院与中科院武汉岩土所签订战略合作协议

正2012年9月广东省建科院与中国科学院武汉岩土力学研究所在广州签订战略合作框架协议,省建工集团徐天平总工,广东省建科院副院长杨仕超、邓浩、陈久照以及相关技术研究科室领导和技术人员参加会议,

Mechanical response of roof rock mass unloading during continuous mining process in underground mine

Taking the test stopes during continuous mining induced roof caving of Tongkeng ore-body No.92 as example, the calculation flow of unloading analysis was established. According to the unloading region division method of the affected zone theory, and the deterioration laws of mechanics parameters of unloading rock mass, the continuous mining process in underground mine was analyzed by the software MIDAS/GTS, the mechanical response of roof rock mass unloading was studied, and the differences were analyzed with the conventional simulation. The result shows that the maximum tensile stress, subsidence displacement and equivalent plastic strain of roof rock mass are 1.5 MPa, 20 cm and 1.5% in the unloading analysis, while 1.0 MPa, 13 cm and 0.9% in the conventional analysis. The values of unloading analysis, which are also closer to the actual situation, are greater than those of conventional analysis; the maximum step in continuous mining is 48 m, which shows that the induced treatment of the roof should be carried out after 2 mining steps

Rock-forming mechanism of Qingshanjiao intrusion in Dongguashan copper(gold) deposit, Tongling area, Anhui province, China

Dongguashan deposit is a large porphyry-skarn copper（gold） deposit in Tongling ore district. The Qingshanjiao intermediate acid intrusion of Yanshanian had a direct genetic relationship with mineralization. The magma origin, rock-forming dynamic background and rock-forming process were studied, and the rock-forming mechanism of Qingshanjiao intrusion was discussed, based on geological characteristics, detailed observation of petrography and systematic investigation of petrochemistry, trace elements and REE geochemistry characteristics of Qingshanjiao intrusion. The results show that Qingshanjiao rock body belongs to high-K calc-alkaline series with higher LREE elements, Th, Rb and Sr abundance, but depleted in HREE elements, Ba, Nb and Ta. The primary magma originated from the mantle-crust mixtures which were caused by basaltic magma of mantle mixing with syenite magma of partial melting of the lower crust, and the formation environment of Qingshanjiao intrusion was emplaced in the transitional environment from compression to extension. The Harker diagram and hybrid structures of plagioclase and potassium feldspar indicate that the fractional crystallization occurred in the process of magmatic evolution. The petrochemistry, trace elements and REE geochemistry characteristics indicate that the magma was contaminated by crustal material during the rock-forming. These results suggested that the Qingshanjiao intrusion was formed by fractional crystallization and assimilation and hybridization of mantle-crust magma in the transitional environment from compression to extensional.

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.

SPH-FEM simulations of microwave-treated basalt strength

Microwave precondition has been highlighted as a promising technology for softening the rock mass prior to rock breakage by machine to reduce drill bit/cutter wear as well as inverse production rate.To numerically explore the effect of numerical parameters on rock static strength simulation,and determine the numerical mechanical parameters of microwave-treated basalts for future drilling and cutting simulations,numerical models of uniaxial compression strength(UCS)and Brazilian tensile strength(BTS)were established with the coupling of smoothed particle hydrodynamics and finite element method(SPH-FEM).To eliminate the large rock strength errors caused by microwave-induced damage,the cohesion and internal friction angle of microwave-treated basalt specimens with the same microwave treatment parameters were calibrated based on a linear Mohr-Coulomb theory.Based on parametric sensitivity analysis of SPH simulation of UCS and BTS,experimental UCS and BTS values were simultaneously captured according to the same set of calibrated cohesion and internal friction angle data,and the UCS modeling results are in good agreement with experimental tests.Furthermore,the effect of microwave irradiation parameter on the basalt mechanical behaviors was evaluated.

Effect of impulse and bedding on impact toughness of coal

In order to understand the properties of impact toughness of coal at different impact speeds,and the change of impact toughness of lump coal to joint directivity of lump coal,a series of impact tests were conducted on Beijing Da'anshan Lump Coal at different impact speeds and in different impact direction.Through analyzing the test result,it is shown that the change of testing samples is similar when impact is exerted on the vertical bedding and the parallel bedding when the impulse is less than 20 N.s,and the difference increases with the impulse increasing when the impulse is more than 20 N·s.At the same time,the expanding energy of fracture in samples increases with its expanding speed,and the expanding energy of fracture has close relation with the impact direction of the tested samples.And the difference of impact toughness of lump coal produced by different im- pact direction increase with the impact speed.The fracture surface of lump coal when im- pact is exerted on the vertical bedding is smooth and the broken block number is fewer; but the fracture surface of lump coal when impact is exerted on the parallel bedding isn't smooth and the broken block number is more,which inflects impact toughness of coal is sensitive to some deficiency.

Determination of critical slip surface of fractured rock slopes based on fracture orientation data

The critical slip surface of a fractured rock slope tends to extend along the fractures.Thus,fracture orientation plays a critical role in determining the critical slip surface.Based on fracture orientation data,this paper examines the critical slip surfaces of fractured rock slopes.Given that the surface of a fractured rock slope extends along the fracture surfaces,or the wedges,with each composed of two arbitrary fractures,the critical slip surface is determined via stochastic dynamics.In addition,a fracture frequency method is proposed as a means of analyzing the critical slip surface.According to this method,the critical slip surface slips in whichever direction has the lowest fracture frequency.Based on the stochastic dynamics method and the fracture frequency method,the critical slip surface of the slope is finally determined,that is,the critical slip surface takes the form of a plane passing the slope toe with a dip of 120° and a dip angle of 45°.