基于特质属性分析的传统村落保护规划策略研究——以郑州上街方顶村为例

随着我国城镇化进程的快速推进,传统村落面临着种种问题,比如人口结构失衡、流失严重、经济发展缓慢、物质空间衰败等问题。如何将传统村落更好地保护和传承下去,是近年来村庄规划研究普遍关注的议题。该文以河南历史文化名村方顶村为例,通过村落历史脉络梳理和特质属性分析,进而提出相应的保护规划模式和社会发展策略,以期为传统村落的有机保护与可持续发展提供一些有益思路。

传统肌理中的公共建筑实践--以郑州“方顶驿”游客中心设计方案为例

传统肌理中的公共建筑实践是这个时代不得不面对的课题,解决方式不仅有仿古建筑和由西方引入的现代建筑两种途径,在现代建筑的处理方式中留住历史的痕迹也是一种应对策略。文章以河南郑州“方顶驿”游客中心设计为切入点,从项目概况、历史背景、场地矛盾、设计策略等方面详细阐释了方案的生成过程,试图来回答传统建筑的空间组织方式如何在大体量的公共建筑中延续的问题。

残煤综采放顶煤防灭火技术应用

要使残煤综采放顶煤技术得以推广,并实现安全、高效生产,必须解决开采期间防灭火工作相关问题,完善防灭火措施是重点。此方案的提出,对残采综采放顶煤工作面的安全开采具有积极的指导意义。

Safe roof thickness and span of stope under complex filling body

Longhole caving method was used to mine gently inclined thick orebody step by step in a test stope of tin mine under complex filling body. The problem that the complex filling body around the stope affects the stability of roof thickness, chamber and spacer pillar in actual mining was investigated; meanwhile, the formed goaf during mining is so vulnerable that surrounding rock collapses early. Based on this point, elasticity mechanics and limit span theory were used to study separately the roof thickness and the span limit of goaf formed in mining, and then a reasonable roof thickness of 8 m and goaf span of 14 m are proposed. In addition, the stability of roof thickness, chamber and spacer pillar were investigated and analyzed by using numerical analysis method; meanwhile, the field monitoring on the displacement of caving chamber was conducted. The results show that the maximum compressive stress of surrounding rock is 20 MPa, and the maximum tensile stress is 1.2 MPa, which is less than the ultimate tensile strength of 2.4 MPa. Moreover, plastic zone has little influence on stope stability. In addition, the displacement of 11 mm is also smaller. The displacement monitoring results are consistent with the numerical results. Thus, the roof thickness and span of goaf proposed are safe.

Principles of the roof cut short-arm beam mining method (110 method) and its mining-induced stress distribution

Since the 1960 s, mining science and technology in China has experienced two technical innovations, i.e.the ‘‘Masonry Beam Theory(MBT)" and ‘‘Transfer Rock Beam Theory(TRBT)". Based on those theories, the conventional mining method(being called the 121 mining method) was established, consisting of excavating two tunnels with a pillar left for mining a working panel. However, with increasing mining depth,engineering geological disasters in the underground caverns have been frequently encountered. In addition, the use of the coal-pillar mining results in a large amount of coal resources unexploited. In order to address the problems above, the ‘‘Roof Cut Short-Arm Beam Theory(RCSBT), being called the 110 mining method)" was proposed by He Manchao in 2008. The 110 mining method features the mining of one coal seam panel, excavating necessarily only one roadway tunnel and leaving no pillars. Realization of the 110 mining method includes the following steps:(1) directional pre-splitting roof cutting,(2) supporting the roof by using high Constant Resistance Large Deformation bolt/cable(CRLD), and(3) blocking gangue by hydraulic props. This paper presents an overview of the principles, techniques and application of the 110 mining method. Special emphasis is placed on the numerical simulation of the geostress distribution found in the mining panel using the 110 method compared to that of the 121 method. In addition, the stress distribution on the ‘‘short beam" left by the roof cutting when performing the 110 method was also investigated using both numerical simulation and theoretical formulation.

Characteristics of in situ stress field at Qingshui coal mine

In this study, the characteristics of geological structure at Qingshui coal mine were analyzed. And the hollow inclusion strain cell overcoring method was used to obtain the in situ stress. The effect of in situ stress on the stability of soft rock roadway was analyzed. The results show that the maximum principal stress is in the horizontal direction with a northeast orientation and has a value of about 1.2–1.9 times larger than gravity; the right side of roadway roof and floor is easily subject to serious deformation and failure, and the in situ stress is found to be a major factor. This paper presents important information for developing countermeasures against the large deformation of the soft rock roadway at Qingshui coal mine.

The Effects of Solution Transformations to the System with Color Parameters

The effects of solution transformations to the six- and eight-vertex systems are discussed. There are four kinds of effects, the Hamiltonian of the system is invariant, its coupling coefficients change, some additional terms appear in the Hamiltonian, and the spin of the system is rotated by some angle about axis under these transformations. In all the cases, the systems are still integrable if they are so before the transformation.

Research on Preparation Method of Static Head Space for Volatile Organic Compounds in Drinking Water

[Objective] This research aimed to study the pre-treatment conditions of head space so as to establish a HS-GC determination method, which is suitable for China's conditions, for trace volatile organic compounds in drinking water. [Method]The preparation method of head space was adopted for the volatile organic compounds in drinking water. [Result] The 20 kinds of volatile organic compounds in drinking water all could be detected simultaneously by using HS-GC-FID method,and they all could be separated well. The HS-GC-FID method could analyze the detected substances qualitatively and quantitatively. In addition, this detection method was characterized by larger linear range of concentration, higher precision, higher detection limit and higher recovery rate. [Conclusion] Under certain conditions, HSGC can reduce the loss of volatile organic compound in drinking water and improve the sensitivity of detection. Moreover, the detection results meet the requirements by quality control.

Study of dynamic pressure roadway supporting scheme under condi- tion of thick composite roof

This paper analyzed the strata behaviors of solid-coal roadway, gob-side entry driving and deformation law of surrounding rock in depth under high stress and thick composite roof based on the dynamic pressure roadway as engineering background in Fengcheng mining area, Jiangxi province. The results, both field measurement and numerical simulation show that gob-side entry driving results the deformation of coal roadway main wall, however, entity-coal roadway driving results deformation of main roof and floor. The maintenance state of gob-side entry driving is better than entity-coal roadway, this situation is relevant to thick composite roof layered and easy collapse characteristics. At the same time, this paper put fox＇ward and proved proper dynamic pressure roadway supporting scheme under the surrounding rock condition and stress environment.

Rock burst induced by roof breakage and its prevention

Based on the research on rock burst phenomenon induced by the breakage of thick and hard roof around roadways and working faces in coal mines, a criterion of rock burst induced by roof breakage （RBRB） was proposed and the model was built. Through the model, a method calculating the varied stresses induced by roof breakage in support objects and coal body was proposed and a unified formula was derived for the calculation of stress increment on support objects and coal body under different breaking forms of roof. Whilst the formula for calculating dynamic load was derived by introducing dynamic index Kd. The formula was verified in Huating Mine by stress measurement. According to the formula for stress increment calculating, the sensitivities of dynamic load parameters were further studied. The results show that the thickness and breaking depth of roof, width of support objeet are the sensitive factors. Based on the discussion of the model, six associated effective methods for rock burst prevention are obtained.

Theoretical Analysis and Simulation of Jacking Procedure of Pantadome System

In order to obtain the principle of Pantadome lifting process and make theoretical foundation for practical applications, the core idea of Pantadome was introduced, which is to make a structure become a mechanism by temporarily removing some members during the process of construction.The Abstract motion model was built. By determining the change of the coordinates of the hinge joint and that of each point of the structure, simulative analysis of the mechanical motion of Pantadome was realized. Then general program that simulates the lifting process of Pantadome was developed based on AutoCAD environment by Auto Lisp language. By completing the theoretical analysis of the lifting process of Pantadome, three-dimensional simulation of the lifting process of Pantadome was realized. And it is successfully applied to bidding work of practical engineering.

Winter Olympics Diplomacy,South Korea-DPRK Contacts and US-DPRK Summit:Historic Changes for Korean Peninsula?

The ⅩⅩⅢ Olympic Winter Games in South Korea lit a flame for the dramatic development of inter-Korean relations. Rapid changes in the geopolitical situation on the peninsula since the Winter Olympics in Pyeongchang have included high-level DPRK talks with South Korea, China and the United States. President Xi Jinping＇ s meetings with DPRK leader Kim Jong-un in Beijing and Dalian, and the upcoming Trump-Kim summit on June 12 are all about timing. A new diplomacy on DPRK＇ s part has unfolded out of the extemal pressure the DPRK experienced from the US, China and the international community but also out of the difficulties the DPRK faces in advancing its nuclear options. Unless the DPRK makes substantial concessions, the US will not alter policy. Real success means historic change, not only a reunion of families and an official end to the Korean War, but also a potential shift in the Asian power structure. There are diverse possibilities and much at stake. The fundamental way forward is restarting Six Party Talks and regional mechanism.

Lightweight design of 45000r/min spindle using full factorial design and extreme vertices design methods

Factors for determining the spindle size are the shaft diameter, positions of bearing and motor, and entire length of the spindle. Then, it is important to find the assembling of the optimal design variables, which satisfy the stiffimss and rotational speed required to the spindle. A general full factorial design method was used to verify some factors that affect the natural frequency of a spindle. It is verified that the shorter shaft length and bearing span length represent the higher natural frequency, and there are some effects according to the change in the levels of factors. The detailed spindle dimension is determined by applying an EVD method, which can define the optimal bearing position through considering the limiting condition. Based on the estimated regression model, the optimal spindle size and bearing distance that can improve the primary natural frequency are obtained, and the influence of design factors on the natural frequency is also analyzed.

Suitable retention and recovery technology of floor coal at ends of fully mechanized face with great mining heights

Gateways at faces of great mining heights are mostly driven along the roof of coal seams.For gateway height restrictions,a 1-3 m floor coal is retained,leaving a triangular floor coal at the face ends,causing a loss of coal.In order to improve coal recovery rates and to ensure efficiency of equipment at coal mining faces,we investigated suitable retention methods and recovery technology of floor coal at face ends.The upper floor coal can directly be recovered by a shearer with floor dinting.The lower floor coal is recovered by shearer with floor dinting after advanced floor dinting and retaining a step for protecting coal sides in a haulage gateway.Field practice shows that this method can improve the coal recovery rates at fully mechanized working faces with great mining heights.

The Research of thick seam mining methods

China＇s total coal reserves are enormous, in which recoverable reserves of coal seam thickness ofmineable coal reserves in China accounted for 43% of recoverable reserves When correctly using thick seam mining, mining methods can improve the proper thick seam mining rate and reduce coal loss. Using proper thick seam mining method can effectively reduce the thick seam mining costs. In mining safety, the use of appropriate thick seam mining methods can effectively prevent thick seam mining accidents. But in the process of development and current situation from the perspective of the Chinese coal mining, there are certain aspects of thick seam mining problems. These problems are mainly in the thick seam mining and the coal recovery rate is low, resulting in lots of waste coal. Besides, thick coal mining is less secure, safe and there are frequent accidents. These problems have seriously affected the thick seam mining. And a lot of thick coal seams of coal resources can not be effectively taken out. Now Chinese mining methods in thick seam mining areas are mainly open-pit mining and underground mining exploitation. Because of the open-pit coal burial depth has more stringent requirements, only used in shallow-depth areas. Underground mining is the primary way China is now using in thick seam mining. Underground mining methods include full-height slice mining and mechanized mining caving mining method once adopted. Research on these thick seam mining methods can provide theoretical and technical support for thick seam mining, thick seam mining techniques to enhance the level . I will combine the current situation of thick seam mining in Chinese study with thick seam mining methods, comments and suggestions for the current thick seam mining study

A combined 2D and 3D numerical modeling approach to provide adequate roof support in complex 3D excavations

Traditional methods for assessing effective roof support can be difficult to apply to complex three-dimensional excavations. Through worked examples,the approach of combined two-dimensional and three-dimensional numerical modeling has been shown to be successful in understanding mechanisms of rock failure for unique excavation geometries and geotechnical properties and,in turn,provides adequate roof support recommendations for complex three-dimensional excavations in Australian coal mines. An interactive approach of monitoring and model review during the excavation process is an important part of model support recommendations to ensure rock failure and deformation in the model are representative of actual conditions,to provide effective and practical controls.

Failure mechanism and control technology of longwall coalface in large-cutting-height mining method

The stability control of longwall coalface is the key technology of large-cutting-height mining method.Therefore,a systematic study of the factors that affect coalface stability and its control technology is required in the development of large-cutting-height mining method in China. After the practical field observation and years of study,it was found that the more than 95% of failures in coalface are shear failure. The shear failure analysis model of coalface has been established,that can perform systematic study among factors such as mining height,coal mass strength,roof load,support resistance,and face flipper protecting plate horizontal force. Meanwhile,sensitivity analysis of factors influencing coalface stability showed that improving support capacity,cohesion of coal mass and decreasing roof load of coalface are the key to improve coalface stability. Numerical simulation of the factors affecting coalface stability has been performed using UDEC software and the results are consistent with the theoretical analysis. The coalface reinforcement technology of large-cutting-height mining method using the grouting combined with coir rope is presented. Laboratory tests have been carried out to verify its reinforcement effect and practical application has been implemented in several coal mines with good results.It has now become the main technology to reduce longwall coalface failure of large-cutting-height mining method.

Analytical solutions of hard roof's bending moment,deflection and energy under the front abutment pressure before periodic weighting

The distribution of front abutment pressure is closely related to the force,deformation and energy distribution of hard roof before periodic weighting. So it is necessary to carry out research on the relationship between them. According to front abutment pressure distribution feature,using the location of peak front abutment pressure as the dividing point,coal seam is divided into two parts along the direction of mining: the yield zone that is the area between the faceline and the point where the maximum front abutment pressure occurs,and the elastic zone that is the part before the point of peak front abutment pressure. The proposed mechanical model of unit width hard roof at the panel center before periodic weighting consists of five parts including the yield zone. All parameters of the deflection equations for each of the five parts that satisfy the continuity conditions and natural boundary conditions are obtained by using the Matlab software. The continuous curves of front abutment pressure,deflection,bending moment and bending strain energy density distribution of hard roof are obtained by iterative approximation method,and the relationship between the yield zone width and the above curves are analyzed in detailed.

Research on hydraulic-powered roof supports test problems

The load-bearing characters of hydraulic-powered roof support with dual telescopic legs were analyzed. With a specific type hydraulic-powered roof support with dual telescopic legs for research object, the inside load test problems in factories was analyzed, and the correct test methods were given, which can enhance the test efficiency and make the factories away from the error design of hydraulic-powered roof supports and legs.

A simple theoretical approach for analysis of slide-toe-toppling failure

A prevalent kind of failure of rock slopes is toppling instability.In secondary toppling failures,these instabilities are stimulated through some external factors.A type of secondary toppling failure is"slide-toe-toppling failure".In this instability,the upper and toe parts of the slope have the potential of sliding and toppling failures,respectively.This failure has been investigated by an analytical method and experimental tests.In the present study,at first,the literature review of toppling failure is presented.Then a simple theoretical solution is suggested for evaluating this failure.The recommended method is compared with the approach of AMINI et al through a typical example and three physical models.The results indicate that the proposed method is in good agreement with the results of AMINI et al’s approach and experimental models.Therefore,this suggested methodology can be applied to examining the stability of slide-toe-toppling failure.