The inlet cofferdam of the expansion engineering of Wuqiangxi hydropower station consists of the reserved rock barrier, concrete, soil and stones. The rock barrier is a bedding slope with relatively developed soft interlayers, which results in a complicated geological condition and blasting demolition environment for the cofferdam. In the process of demolishing the bedding rock barrier, it is impossible to break the rock once in a large area according to the economic section of a conventional cofferdam due to the large engineering quantity of the underwater blasting excavation, high requirement of fragmentation, long construction time and high risk. Under the condition of ensuring the stability of the cofferdam, the method of vertical stratification, horizontal zoning and loosening bench blasting was adopted to implement land excavation as much as possible. For the underwater blasting, according to the geological conditions of rock barrier, the mechanical characteristics of rock mass, the water depth (20~37 m) and the fragmentation requirement, the powder factor of 0.9~1.1 kg/m3 and maximum charge per delay of 60 kg was adopted. Electronic detonators were used for blast hole initiation and a series of safety measures such as bubble curtains and flexible protective nets were set. The field monitoring results show that the effect of blasting vibration and water percussive wave on structures such as inlet gate has been effectively controlled, and the efficiency of underwater slag removal and transfer has been improved.

进水口基坑施工受高水头及多次重复爆破影响,施工过程中的安全风险高,针对施工风险评价具有模糊性和随机性,提出基于云模型的基坑爆破施工风险评价方法.从工程环境因素、施工作业因素、施工管理因素等方面进行危险源辨识,确定进水口基坑施工风险评价指标体系,应用层次法对评价指标进行赋权,通过云发生器生成风险云图,直观地对基坑施工风险因素进行分析及评价.实例应用结果表明:将层次法与云模型相结合,提出的基于云模型的进水口基坑施工安全评价方法合理可行,可为类似水工建筑物基坑施工安全评价及控制提供借鉴.

In order to study the influence of excavation diameter on the rockburst damage of deeply buried tunnels, three different hole diameters of large-size specimens of rock-like materials were tested in real triaxial rockburst model, and the whole process of loading damage was monitored by intelligent cameras and acoustic emission monitoring system, and the influence of different hole diameters on the rockburst of specimens was compared and analyzed.The results show that the specimens with different hole diameters experienced three stages of initial damage（Ⅰ）,damage development（Ⅱ） and damage failure（Ⅲ） during the loading process.As the hole diameter increases, the damage load of the specimen decreases, the damage range and debris mass of the rockburst increases, and the proportion of large debris mass increases.Loading process acoustic emission event energy maximum with increasing hole diameter is decreasing trend, while the cumulative energy is increasing trend, reflecting the smaller hole diameter specimen damage more concentrated energy release, the more intense rupture, the larger the hole diameter, the larger the overall scale of cracking within the specimen.The overall b-value of acoustic emission during loading decreases with the increase of hole diameter, reflecting the decrease of fragmentation and the increase of large scale rupture of specimens with the increase of hole diameter.In the damage failure（Ⅲ） stage, the proportion of low and medium frequency high amplitude acoustic emission events increases with the increase of hole diameter, reflecting the lower degree of fragmentation of the surrounding rock damage and the increase of large scale rupture with the increase of hole diameter of the specimen.The damage rupture scale of the specimen at each stage reflected by the time-frequency characteristic parameters of acoustic emission is consistent with the macroscopic damage phenomenon of the specimen.

应变型岩爆是在深地下开挖引起围岩应力集中后受梯度应力作用下产生的.为探明围岩应力梯度对应变型岩爆围岩破坏及特征荷载的影响,采用自主研发的真三轴气液复合加卸载岩爆模拟试验装置,在相同模型材料、围压与单面卸载条件下,进行了4种竖向梯度应力加载的岩爆模型试验.试验采用类岩石材料的大尺寸(1000 mm×600 mm×400 mm)试件实现竖向梯度应力加载,模型材料选取具有强岩爆倾向的水膏比为0.7的石膏材料.基于岩爆模型试验的宏观破坏现象观察及加卸载过程的声发射能量与累计能量曲线,分析了竖向加载应力梯度系数对试件岩爆破坏特征的影响规律.基于试验过程的加载应力及声发射振铃总计数曲线的阶段性变化分析,获得了4种不同竖向梯度应力加载条件下试件的峰值荷载、起裂荷载与损伤荷载.结果表明:随着竖向加载应力梯度系数的增大,岩爆碎屑由大块板状为主逐渐过渡到以小块片状、块状与粉末状为主,岩爆碎屑的弹射最大距离逐步增大,岩爆的动力破坏现象越来越来越明显;试件在破坏过程中释放的累计能量逐渐减小,能量释放越来越趋于临近岩爆前集中释放;试件的起裂荷载趋向于增大,损伤荷载则变化不大,峰值荷载减小.

土力学实验课程是工科高等院校在实践教学中的重要部分,因成绩评定时需考虑的因素较多,且受教师主观因素的影响大,用常规的评定方法难以形成准确的分值.为了对学生的成绩做出相对公平的评分,该文分析实验课程评分过程中存在的问题,尝试运用模糊层次分析法,通过对实验过程中不同考核指标进行定性评价,利用模糊矩阵实现从定性评价到分数定量的转变,最后得到相对客观合理的分数.该方法具有较好的可操作性,能多层次、多角度实现实验课成绩评定标准,能为高校同类型实验系列课程成绩提供参考和示范作用.

为了探讨不同类型围岩储存能量特性对岩爆的影响,应用气液复合加载岩爆模型试验装置,采用0 MPa、2 MPa、3 MPa三种初始蓄能气压模拟不同类型围岩储存能量特性,进行了梯度加载岩爆模型对比试验,对试件宏观破坏特征、内部应力和破坏瞬间的应变特性及声发射特征参数进行了系统的研究.结果表明:通过气液复合加载器蓄能腔中不同初始蓄能气压大小的设置可以达到定性模拟不同类型围岩储存能量特性对岩爆的影响分析,初始蓄能气压越大(围岩储存能量能力越强),试件破坏瞬间的应变越大,卸载面应力集中程度越高,破坏历时越短,能量释放的速率越快,岩爆破坏越显著;气液复合加载较液压加载,对于岩爆现象的发生及烈度有促进作用.

为了进一步提高学院实验教学质量,基于实验教学成绩评定标准,分析学院土力学实验课程教学现状和存在的问题,查找实验教学体系设计缺陷,在以往专业实验基础上增设专业基础实验,修订实验成绩评定方案,探讨实验教学改革及实验管理方式,优化实验教学成绩评定体系.结果表明,基于实验课成绩评定的实验教学改革能较好地改善实验教学效果,进一步完善实验教学方法,切实提高学生的创新和动手能力,培养其独立开展科学研究的能力和素养.

To study the influence of gradient stress on the evolution characteristics of the temperature field during rockburst, the gradient and hydraulic-pneumatic composite loading true-triaxial apparatus was used to perform the rockburst tests under true-triaxial gradient loading. The temperature data of the unloading face of each sample under gradient loading were continuously recorded using the infrared thermal imager until the rockburst occurred. For the high-temperature points in temperature field, the variance-mean ratio (VMR) was introduced and the relative average temperature of high-temperature points (RAHPT) was proposed for joint analysis to quantify the evolution characteristics of temperature field. It was found that: (1) the VMR and RAHPT adopted in this paper successfully reflect the evolution characteristics of the temperature fields of all the samples under different stress gradients. The VMR and RAHPT increase initially with the increasing loads but subsequently show upward or downward trends in the late stage of loading under different stress gradients; (2) the VMR and RAHPT curves of each sample exhibit similar trends and obvious changes in phase with the increasing load; (3) the samples show obvious differences in rockburst precursors under different stress gradients, and the temperature differentiation of unloading faces appears shortly before the rockbursts, accompanied by the sudden increases in the VMR and RAHPT curves under high stress gradients; (4) the temperature anomalies that occurred on the samples under loading indicate the damage zones of the impending rockbursts. The research results provide a theoretical basis for infrared early-warning technology of rockbursts in underground openings.

针对特大型危岩体爆破削方治理过程中的风险因素具有随机性和不确定性,基于云模型理论,提出了组合赋权的危岩体云模型风险评价方法.从危岩体地质条件、环境因素、爆破削方施工及施工管理四个方面进行危险源辨识,建立特大型危岩体爆破削方治理风险控制安全评价指标体系,应用层次分析法对评价指标进行组合赋权处理.结合正向正态云模型和指标权重,计算评价对象的确定度及风险等级.应用该方法对甑子岩特大危岩体爆破削方治理过程进行了风险评价.该工程根据风险分析进行的危险源施工控制,能够满足施工安全.

为揭示顺层岩质边坡爆破振动传播规律,采用起爆药量分别为3.2 kg、4.8 kg、4.8 kg和7.2 kg,完成现场4次爆破试验,通过沿边坡走向和坡面倾向各布置4组测点,获取振动速度监测数据.利用回归分析方法,分析不同位置的振动速度衰减规律,得到了顺层岩质边坡不同爆破开挖药量与振动速度的关系,提出了一次最大安全起爆装药预测表达式;并通过数据拟合,得到多次爆破作用下垂直与水平方向振动速度的衰减参数与药量的关系式.最后,采用3DEC数值分析方法,模拟了振动应力波在顺层岩质边坡中的传播过程,反映了顺层岩质边坡在考虑岩层走向和倾向时的振动速度变化规律,为同类型的顺层岩质边坡爆破安全控制提供参考.

为了探讨深埋地下洞室在岩体自重应力作用下的岩爆破坏特征,采用自主研制的岩爆模型试验装置进行了室内模型试验,分析了洞室岩爆的宏观破坏现象及围岩的应变特征;在此基础上通过数值计算方法模拟分析了不同侧压系数对深埋洞室岩爆破坏过程及破坏区域的影响.研究结果表明:洞室围岩在加载过程中的变形规律基本呈对称状态,侧压系数λ为1/3模型试验,洞室侧壁部位是发生岩爆破坏的主要区域,其破坏范围约为20％的洞室直径,模型试验的宏观破坏范围与数值计算的破坏区域及影响范围基本一致;当侧压系数λ发生改变,深埋洞室发生岩爆破坏时的荷载和区域也随之变化,洞室发生破坏时的临界荷载随λ的增加而增大;当λ为1/3和1/2时,破坏区域主要集中于洞室两侧壁;当λ为1时,破坏区域集中于洞室顶部,并由洞顶向洞壁扩展.采用物理模型和数值分析相结合的方法,进行不同应力状态下的岩爆破坏特征研究具有一定的可行性.

The cutting amounts of Zengziyan oversize dangerous rock mass is large,the construction duration is long and the environment is complex.During the construction process,proper blasting zone and reasonable safety con-trol measures were adopted to effectively reduce the effect of blasting on the stability of rock body.The hole-by-hole millisecond delay blasting method with detonators relay explosion from inside of hole to outside,and pre-splitting blasting technology were used,finally a relatively smooth excavation slope surface was obtained,where the half-hole rate was high and the overall blasting effect was good.In the construction process,the velocity of blasting vibration of the surface dangerous rock mass with certain distance to blasting center,was used as the control standard for stability monitoring to effectively reduce the influence of blasting vibration on parent rock and dangerous rock mass,which met the requirement of rapid control and vibration control of dangerous rock mass,and helped to regulate blasting con-struction process control.

High control accuracy and small range of damage are required in underground plant rock bench exca-vation,therefore the excavation is difficult and construction requirement is high.In practical engineering,engineering analogy and blasting test in a similar location are always used.Due to the occurrence conditions in rock and restric-tions on site,it is inconvenient to compare test results of different combinations of blasting parameters.Based on the engineering practice of GD-3,using the ANSYS/LS-DYNS software,the simulations of rock bench blasting under sin-gle hole and porous condition were carried out by changing the charge density and hole spacing.The better rock blas-ting parameters were obtained,and conducted in a live blasting test.According to the calculation of the recommended blasting parameters for construction,a more ideal rock bench forming quality is obtained,which can provide reference for similar projects.

为了探讨液压与气液复合加载条件下地下洞室岩爆现象的差异,选择具有明显脆弹性的石膏模型材料,制作了大尺寸模型试件,利用自主研发的气液复合型岩爆模型试验装置开展液压与气液复合加载洞室岩爆物理模型试验,模拟深部地下洞室开挖过程中的岩爆现象.采用应力应变测试、 声发射监测及影像获取等方法,对试件加载过程中洞室的宏观破坏现象、 洞室周边内部变形规律、 声发射特征参数及裂纹的扩展进行分析.试验结果表明:洞室边墙和拱肩部位产生较大的应力集中区,洞室岩爆破坏顺序是先边墙,后拱肩方向,边墙和拱肩部位在极短的时间内出现裂纹及扩展,形成较大范围的层裂、 剥落及弹射碎片,并伴随较大的声响;在相同的加载应力路径下,气液复合加载较液压加载破坏区范围更大,在本试验气液复合加载条件下,边墙破坏区范围大致为0.6b(b为洞室宽度);岩爆的发生及烈度与加载方法和破坏时能量的释放速率密切相关,采用气液复合加载的模型试件,在对应破坏点处应变具有明显的梯度变化,应变值显著高于液压加载试件,同时,声发射能量较液压加载具有明显的突变,岩爆的宏观破坏过程及现象更为明显,破坏程度更为剧烈.气液复合加载的试验方法更为符合实际工程岩体破坏过程的实际受荷.

To overcome the deficiency of the existing test devices and methods for rock burst modeling，a gas-liquid composite loading test device was developed to conduct the large size rock burst modeling under different stress gradients. In this paper, the occurrence，development processes and failure mechanism of the rock burst were studied through the analysis of the macroscopic failure features，interior deformation characteristics and the acoustic emission characteristic parameters of the sample. The results show that the occurrence of rock burst is closely related to the stress gradient，the energy concentration degree and the energy release rate during the rock burst processes. The differences of load gradient difference in the model test lead to the different concentration degree of internal stresses. These differences also influence the energy dissipation and agglomeration of the specimen in the early stage and the energy release rate at the moment of rock burst. If the difference of the vertical fracturing load gradient becomes greater，the degree of the local stress concentration becomes higher and the energy release rate will be faster. At the same time，the energy converted into the kinetic energy will increase and the probability of rock burst will be larger. When the specimen is broken，the ratio of the maximum vertical load on the top to the uniaxial compressive strength R is . Under the gradient loading condition，the static and dynamic composite loading is the main reason for the reduction of the failure load capacity of the specimen.

Focused on the blasting vibration in the blasting excavation of oversize dangerous rock mass,a numerical simulation model according to the characteristic of dangerous rock mass was established by FLAC3D,where the dangerous rock mass was divided into slices,and the blasting dynamic loads of different single dose were calculated and input to get the acceleration of mass point in each slices.Besides,equivalent acceleration method based on rigid limit equilibrium equation was adopted to analysis the stability of dangerous rock mass dynamic behavior,further to work out the relations between safety factor and single dose,finally the maximum single dose corresponding to suitable safety factor was obtained according to related standards.Improved blasting effect was testified by the site blasting experiments.In addition,with the relationship between vibration velocity and explosion center distance,the vibration velocity in required distance from explosive source could be considered as the site standards under the controlled charge quantity.

To study acoustic emission(AE)characteristic parameters of the process of rock burst and the re-lationship of rock burst damage,the rock burst test for large size specimen(1 000 mm×600 mm×400 mm) was carried out using the self-developped model test device.AE monitoring data was obtained in the process of rock burst under different loading gradients by using AE monitoring devices.Results show that in the process of gradient loading,the number of AE events and the energy of the specimen are different in different loading time,exhibiting great gradient change.In the early stage of loading,the AE signal is very few.The greater the abrupt change of rock burst,the greater the energy of the specimen gathering,and more likely strong rock burst phenomenon occurs in an instant.The AE location point can reflect the dy-namic evolution process of the internal crack of the specimen.In the process of gradient loading,the distri-bution and quantity of AE location point can directly display the degree of rock burst damage.

利用FLAC3D,模拟设计要求和最不利状态情况下某地铁车站深基坑工程开挖.研究得出土岩基坑的变形规律特点,模拟结果同时表明:基坑周边的荷载对土体沉降影响较大,对支护桩侧向位移影响较小,且车辆荷载比堆载影响大；有无支撑对基坑变形影响较大.

The quality requirement of weathering rock slope excavation by blasting is higher.The optimal construction method and blasting parameters were determined according to the slope rock conditions.The blasting experiment was carried out to verify the rationality of the blasting parameters,and evaluated the experiment result with the digital bore panoramic camera system,which used to test the blasting result.The test results show that the blasting scheme can meet the slope stability control requirements,and less damage on rock mass,which give some help to improve the blasting results and improve the efficiency of construction.

Based on the blasting vibration field test of a high cutting rock slope of Guanghe expressway in Guangdong province, numerical simulation is employed to estimate the dynamic behavior of the slope under blasting load. A simplified triangular blasting load is adopted to simulate the explosion. The velocity and displacement fields of the slope under blasting are analyzed and the result shows that the particle vibration velocity by the numerical simulation is basically consistent with that by field test. Elevation amplification effect exits in the process of attenuation of the particle peak velocity. The result also indicates that the particles on the surface of the slope have larger velocity and maximum displacement than the particles inside the slope, and the maximum displacement of particles does not have obvious rule to comply with.