摘要：Evapotranspiration(ET)is of great significance for the ecological environment and water resource utilization in arid and semi-arid *** Mongolian Plateau,owing to drought,low rainfall,and extremely uneven distribution of water resources,has a typical temperate continental climate.A refined understanding of the spatiotemporal distribution of ET in this region will help in establishing regulatory strategies for climate change responses,regional livestock regulation,and grassland degradation *** this study,meteorological station data,precipitation data,and the Penman-Monteith model were used to study the temporal and spatial distribution characteristics of actual ET over the Mongolian Plateau from 2011 to *** found that:(1)The spatial distribution of ET in the Mongolian Plateau showed a high trend in the north and east and a low trend in the middle and *** was a significant difference in the regional annual ET,with the highest ET reaching over 500 mm and the lowest being only approximately 70 mm.(2)The annual ET values in 2013,2018,and 2019 were relatively large,varying between 80 and 500 mm,and the overall ET of the Mongolian Plateau first decreased,then increased,and then decreased.(3)The temporal distribution exhibits a unimodal trend of increasing and then decreasing,with July being the turning ***-September was a period of high ET,with the highest ET exceeding 100 *** vegetation coverage was high,precipitation was abundant,and the vegetation ET effect was *** was a period of low ET,with a maximum ET of approximately 10 mm in January and December;the ET for the month with the lowest value was approximately *** quantitative inversion method proposed in this study can provide method and data support for north and central Asia,and other large arid and semi-arid areas.

摘要：A deterministic approach is frequently used in engineering design. In this quantitative design methodology, a safety factor, which is typically a strength-to-stress ratio, is derived as an index for the stability assessment of the engineering design. In underground coal mining applications such as pillar design,however, the inputs of pillar design are variables. This is widely overlooked in the deterministic approach. A probabilistic approach assessing the probability of failure or reliability of a system might be an alternative to the conventional quantitative methodology. This approach can incorporate the degree of uncertainty and deviations of variables and provide more versatile and reliable results. In this research, the reliability of case histories from stable and failed pillars of South Africa presented by Merwe and Mathey is examed. The updated Salamon and Munro strength formula(S-M formula) and Merwe and Mathey strength formula(M-M formula) are evaluated through a probabilistic approach. It is concluded that stable pillar cases have a reliability value greater than 0.83 while the reliability value of failed pillar cases are slightly larger than 0.50. There seems to be a positive relation between safety factor and reliability. The reliability of a pillar increases with pillar width but decreases with depth of cover, pillar height and entry width. The reliability analysis also confirms that M-M strength formula has a better distinction between the stable and failed pillar cases.

摘要：In recent few years, significant improvement has been made in developing largescale 3 D printer to accommodate the need of industrial-scale 3 D printing. Cementitious materials that are compatible with 3 D printing promote rapid application of this innovative technique in the construction field with advantages of cost effective, high efficiency, design flexibility and environmental friendly. This paper firstly reviews existing 3 D printing techniques that are currently being used in commercial3 D printers. It then summarizes three latest development of largescale 3 D printing systems and identifies their relationships and limiting factors. Thereafter, critical factors that are used to evaluate the workability and printable performance of cementitious materials are specified. Easy-extrusive, easy-flowing, well-buildable, and proper setting time are significant for cementitious material to meet the critical requirements of a freeform construction process. Finally, main advantages, potential applications and the prospects of future research of 3 D printing in construction technology are suggested. The objective of this work is to review current design methodologies and operational constraints of largescale 3 D printing system and provide references for optimizing the performance of cementitious material and promote its responsible use with largescale 3 D printing technology.

摘要：A simplified method was proposed for the design of concrete lining in underground rock cavern/tunnel against shock loading. The loading may result from the detonation of explosives on ground surface or ground penetration projectiles exploding adjacent to the cavern/tunnel. The resulting problem necessitates the solution of the dynamics of a beam loaded by a transient pressure uniformly distributed over the span. According to mechanical characteristics of the system with rock bolt and shotcrete, a dynamic support design method based on equivalent single degree of freedom （SDOF） was put forward. The SDOF method was applied to obtaining the maximum displacement at the mid-span of the beam, which is often the controlling factor in the blast-resistant design. In the formulation of the problem, the proposed method combines the phenomena of spalling and structural dynamics theory. An example is provided to demonstrate the applicability of this simplified method.

摘要：Based on the performance results of the previously suggested smart building isolation systems （lst companion paper）, this following study verifies the control effects of the systems from the view point of energy dissipation and damage level metrics. Several different model cases of the strategically isolated multi-story building structures utilizing passive dampers and semi-active resettable devices are analyzed and the energy-based target indices are compared. Performance comparisons are conducted on statistically calculated story/structural hysteretic energy and story/structural damage demands over realistic suites of earthquake ground motion records, representing seismic excitations of specific return period probability. Again, the semi-active solutions show significant promise for applications ofresettable device, offering advantages over passive systems in the consistent damage reductions. The specific results of this study include the identification of differences in the mechanisms by which smart building isolation systems remove energy, based on the differences in the devices used. Less variability is also seen for the semi-active isolation systems, indicating an increased robustness.

摘要：Based on the height of back-filled materials, thickness of ore body, height of boundary pillar and dipping angle of ore body and water pressure, the safety factors of all the pillars are calculated with the limit equilibrium method. The calculation results present that the safety factors of pillars in Sections 19, 20, 24, 28 are less than 1.3, and those of unstable sections are identified preliminarily. Further, a numerical investigation in Sections 18, 20, 22, 24, 25 and 28 implemented with numerical code RFPA20 is employed to further validate the pillar performance and the stability of stopes. The numerical results show the pillars in Sections 18, 22 and 24 are stable and the designed pillar size is suitable. The width of the ore body near Section 28 averages 20 m, failure occurs in the left stope, but the boundary pillars near Section 28 maintain good performance. The pillars in Sections 20 and 25 are unstable which are mainly affected by the Faults F8 and F18. The existence of faults alters the stress distribution, failure mode and water inrush pathway. This work provides a meaningful standard for boundary pillar and stope design in a mine as it transitions from an open pit to underground.

摘要：The turbulent flow in the draft tube of a Francis turbine is very complicated while working under off-design conditions. Although the off-design conditions were widely studied, the vortex core line in the draft tube of a Francis turbine with splitter blades is not well understood, especially the vortex rope property. This letter presents a prediction of the behavior of the vortex rope in the draft tube of the Francis-99 turbine obtained by the computational fluid dynamics (CFD), where the Liutex/Rortex method, as the most recent vortex definition, is applied to analyze the periodical precession of the vortex rope in the draft tube cone. The advantage of this Liutex/Rortex method is shown by its enhanced ability to represent the vortex rope structurewith the vortex-core lines. Furthermore, since it seems to be very hard to define a sharp boundary surface for the whole vortex structure, it is advantageousfocusing only on the vortex core line,by which different vortex structures can be clearly differentiated. The evolution of the vortex core and the process of the vortex breakdown in the draft tube are revealed, which might help to comprehend the development of the turbulent flow in the draft tube.

摘要：Darcy's law only applying to the flow domain is extended to the entire fracture network domain including the dry *** partial differential equation(PDE) formulation for unconfined seepage flow problems for discrete fracture network is established,in which a boundary condition of Signorini's type is prescribed over the potential seepage *** order to reduce the difficulty in selecting trial functions,a new variational inequality formulation is presented and mathematically proved to be equivalent to the PDE *** numerical procedure based on the VI formulation is proposed and the corresponding algorithm has been *** a continuous penalized Heaviside function is introduced to replace a jump function in finite element analysis,oscillation of numerical integration for facture elements cut by the free surface is eliminated and stability of numerical solution is *** numerical results from two typical examples demonstrate,on the one hand the effectiveness and robustness of the proposed method,and on the other hand the capability of predicting main seepage pathways in fractured rocks and flow rates out of the drainage system,which is very important for performance assessments and design optimization of complex drainage system.

摘要：The hydraulic characteristics of artificial waterfalls constitute an important research area for both academia and industry. As yet, the hydraulic parameters used in the hydraulic design of landscape waterfalls are not well understood for use in qualitative and quantitative analyses. Due to their complicated shapes and appearances, it remains a challenging problem to design or simulate realistic waterfall scenes. In this paper, we present a hybrid model and an efficient numerical method for simulating the hydraulic characteristics of waterfalls and investigate the critical flow in waterfall design and the adherent flow phenomenon. We fit empirical equations to predict the size and shape of different waterfall flow patterns to provide a basis for the design and construction of waterscapes in the real world. We then apply our work to an artificial waterfall in Kraal Jiang River and the results demonstrate that our model achieves desirable control qualities and good agreement in a real-world application. © 2017, Tianjin University and Springer-Verlag Berlin Heidelberg.

摘要：含预切空腔的轮廓爆破技术被认为是改善高地应力下隧道轮廓成型的有效方法。然而,对这种爆破技术在不同地应力下性能的研究较少。本文通过校验后的公路隧道数值模型,调查了含预切空腔(PC)的两种典型轮廓爆破技术(即光面爆破(SB)和预裂爆破(PB))在不同地应力条件下的性能。结果表明,在耦合装药和50 MP地应力下,PCSB比PCPB能获得更好的隧道轮廓成型效果。此外,研究了两种轮廓爆破技术在不同的不耦合系数和地应力条件下的性能,发现随着地应力从30 MPa增加至50 MPa,PCSB和PCPB作用下隧道轮廓成型效果均逐渐改善。此外,在不同地应力条件下调整周边孔的不耦合系数能使PCPB形成有效的隧道轮廓。然而,对于PCSB,在不同地应力条件下,需调整所有炮孔的不耦合系数才能形成符合要求的隧道轮廓。最后通过多元非线性回归获得经验公式,本研究可以为不同地应力下使用PCSB和PCPB开挖隧道提供设计参考。