地下井体建设对地磁观测场地的干扰

以大连地震监测中心地震前兆观测新建地下井体为例,基于场地梯度测量方法,定量分析井体建设对地磁观测场地的干扰。基于观测井设计数据,计算其理论干扰距离,发现最大干扰距离s=456.6 m>270 m(二者的实际间距),推测此地下井体会对地磁观测产生干扰。以井体与地磁观测仪器室之间50 m×160 m的范围为测量区域,以10 m×10 m的网格进行测线及测点的布设,计算并对比分析井体建设前后各测线地磁总场强度F的梯度值,结果发现,除个别临近办公区的测点梯度值不稳定,其他测点梯度值基本处于重合状态,排除测量区域葡萄架和接线井的干扰后,磁场梯度整体符合规范,即ΔF_(b)≤1 nT/m。分析认为,地下井体对地磁场的最大干扰距离为160 m,表明该中心地下井体建设不会对地磁观测场地造成干扰。

南京报恩寺遗址模拟地宫开挖中及成型后的井体特征

南京报恩寺地宫考古发掘完成后,地宫出现了众多病害,直接危及到遗址保存。国内外还无针对地宫类遗址保护的成熟经验,而地宫遗址的加固迫在眉睫。在研究对象附近开挖了一个相同岩土条件、等尺寸的模拟地宫,通过对模拟地宫开挖中和成型后井体变形、含水量、井内水位的监测,查明了模拟地宫井体的变化特征。研究成果有效地揭示了地宫遗址发掘过程中及发掘后井体的动态响应过程,再现了地宫遗址破坏过程,为保护加固地宫的方案设计奠定了科学的地质基础。

Study on the general layout of semi-submersible offshore drilling platforms based on process flow

The general layout of 6th generation semi-submersible drilling platforms is the main factor impacting the efficiency of their drilling operations. This paper provides a compound/integrated algorithm based on process flow that is aimed at improving efficiency, while giving attention to stability and safety at the same time. The paper describes the process flow of dual drilling centers and a hierarchical division of rigs based on the different modes of transportation of various drilling support systems. The general layout-centripetal overall arrangement spatially was determined based on drilling efficiency. We derived our modules according to drilling functionality; the modules became our basic layout units. We applied different layout algorithm to mark out the upper and lower decks. That is, the upper deck was designed based on the lowest transportation cost while the lower deck＇s calculations were based on the best-fit scope. Storage configurations in columns and pontoons were also considered for the layout design. Finally the center of gravity was taken into consideration and the general layout was adjusted accordingly, to result in an optimal center of gravity. The methodology of the general layout can provide a reference for implementation of domestic designs of semi-submersible rigs.

故障水源井的诊断及修复技术

针对水源井常见故障形式,结合故障诊断方法,分别给出了水源井出砂,井体淤塞和井内落物等故障形式的修复方法,并对供水水源井的维护管理提出了合理建议。

红层地区极端干旱条件下的水资源开采问题

本文通过对云南省普洱市江城县2010年抗旱突击找水区域中地层、地质构造、成井工艺的对比,找出地下水的富集规律,最优开采方法,对今后在红层地区地下水资源的勘查、开采、研究上具有一定的指导意义。

浅谈水闸沉井基础施工技术

在钱塘江沿岸水利工程建设中,采用沉井基础,迄今有30多年的历史.作者从长期的施工实践中,摸索了一些经验与体会.主要介绍水闸的单井沉放和多井间隔沉放的沉井基础施工技术.

沉井施工的纠偏技术

在沉井施工过程中，很多因素很容易造成井体的偏斜，如土质、机械的选择、人为因素等等；沉井出现偏斜后，通过分析，在纠编过程中使用有针对性的方法进行纠编，使井体能较快地恢复平稳，使井体能快速下沉。

Study on the evaluation index system and evaluation method for self-elevating drilling unit design

In the process of designing self-elevating drilling unit, it is important, yet complicated, to use comparison and filtering to select the optimum scheme from the feasible ones. In this research, an index system and methodology for the evaluation of self-elevating drilling unit was proposed. Based on this, a multi-objective combinatorial optimization model was developed, using the improved grey relation Analysis （GRA）, in which the analytic hierarchy process （AHP） was used to determine the weights of the evaluating indices. It considered the connections within the indices, reflecting the objective nature of things, and also considered the subjective interests of ship owners and the needs of designers. The evaluation index system and evaluation method can be used in the selection of an optimal scheme and advanced assessment. A case study shows the index system and evaluation method are scientific, reasonable, and easy to put into practice. At the same time, such an evaluation index system and evaluation method will be helpful for making decisions for other mobile platforms.

Stability control of gate groups in deep wells

In order to study stability control methods for a deep gate group under complex stresses,we conducted field investigations and analyses of reasons for damage in the Xuzhou mining district.Three reasons are proposed:deep high stress,improper roadway layout and support technology.The stability control countermeasures of the gate group consist of an intensive design technology and responding bolt-mesh-anchor truss support technology.Our research method has been applied at the -1000 m level gate group in Qishan Coal Mine.Suitable countermeasures have been tested by field monitoring.

Geologically controlling factors on coal bed methane （CBM） productivity in Liulin

It is of great significance to forecast high yield of CBM wells and analyze dynamic production by having an overall study on the characteristics of the produced CBM and determining the main factors influencing the productivity of CBM. With the test report and the related geological parameters of a single well, methods of combining the productivity data and typical production curves were used to analyze different geological factors and how to influence the capacity of a single layer. Then, the paper proposed a new understanding about capacity characteristics of the study area and geological control factors： First, the Shanxi formation production capacity characteristics was divided into two-stages, showing signs of gas and gas break- through for 100 days. Second, two parameters, which include potential of gas production and gas production capacity, were bet- ter than the single parameter, such as gas content, coal thickness, and penetration to analyze affecting factors of single well pro- duction. Finally, comprehensive analysis concluded that the ratio of critical desorption pressure to reservoir pressure has greater influence on the production of vertical CBM wells. Besides, the potential of gas production capacity has greater impact at stage of showing gas signs; the coal reservoir pressure and gas production capacity have greater impact at stage of gas breakthrough for 100 days. Thus, to seek the coal bed methane with high ratio of critical desorption pressure to reservoir pressure and high yield of gas will be important guarantee to the success of the coal bed methane exploration and development.

Adsorption and desorption on coals for CO_2 sequestration

Adsorption and desorption of carbon dioxide, methane and other gases on coals has been investigated experimentally using representative Zhongliangshan coals. Gas adsorption is one of the major concerns for both CO2 sequestration and methane recovery processes. The experiments were carried out using both single and multi-component mixtures at 25 ℃ and 30 ℃ with the highest pressure of 12 MPa. The coal was under moisture equilibrated conditions. This provides experimental data from which a predictive assessment of CO2 sequestration and/or methane recovery can be conducted. The results show that for pure gasses the CH4 adsorption capacity is higher than the N2 adsorption capacity but lower than the CO2 adsorption capacity. Injection of CO2 or other gases into the coal significantly affects CH4 desorption. This allows the enhancement of CH4 recovery from the coals, thus supplying more clean energy while sequestering significant amounts of CO2 thereby reducing the greenhouse effect from human beings.

Research and development on foam breaking and recycling technology in air-foam drilling

In recent years,air-foam combining the advantages of both liquid and air drilling has been utilized as a drilling medium. Air-foam drilling has proved its efficiency in numerous situations where serious problems were encountered,such as in fractured formations and depleted or high permeable zones. However,the major disadvantage of air-foam drilling system is that the foam can only be used once,so that an extremely large pit is required to contain the foam to allow sufficient room for cuttings and for the foam to dissipate. Moreover,it needs enormous volume prepared,consuming abundance of water and ingredient additives,which results in the high cost of foam drilling. The recycling foam fluid by using foam breaking technology is the only effective method to solve these problems associated with the known foam drilling. Various types of equipment and technique have been employed to suppress foam formation in biological and process equipment in foam drilling. The study described various methods of foam breaking technology,and the trend of the foam breaking technology for foam drilling is discussed.

Effective goaf gas capture design at Ravensworth Underground Mine

This paper highlights a reliable goaf gas capture system developed and used at Ravensworth Under-ground Mine since its trial in 2009. The method utilises horizontal holes drilled from underground sites and connected to an underground gas pipeline. This system incorporates a gas suction and flaring plant designed specifically for this method. The current method has captured effectively a total longwall, and adjacent goaf gas accounts for over 85%. The design of the holes drilled has been the success of the gas flow reliability. The flow is extraordinarily consistent and predictable. The management of the under-ground pipeline determines the overall reliability of flow. The design has resulted in Ravensworth Man-agement being confident to remove a gas bearing bleeder roadway and still manage the existing tailgate roadway for allowing access as required. The reduction of CO2 equivalent emissions recorded is approx-imately 0.35 ？ 106 tons annually. This design has further improvements to be added to allow use at any other site with gas in the overlying strata.

A value adding approach to hard-rock underground mining operations: Balancing orebody orientation and mining direction through meta-heuristic optimization

Underground mines require complex construction activities including the shaft, levels, raises, winzes and ore passes. In an underground mine based on stoping method, orebody part(s) maximizing profit should be determined. This process is called stope layout optimization (SLO) and implemented under site-specific geotechnical, operational and economic constraints. For practical purpose, the design obtained by SLO shows consecutive stopes in one path, which assists in defining the mining direction of these stopes. However, this direction may not accommodate the spatial distribution of the ore grade: if the orebody orientation and mining direction differ, the value of the mining operation may decrease. This paper proposes an approach whereby paths in the SLO are defined as decision variables to avoid the cost of mining in the wrong direction. Furthermore, in the genetic-based formulation, which accounts for orebody uncertainty, a robust cluster average design process is proposed to improve SLO’s performance regarding metal content. A case study in narrow gold vein deposit shows that the profit of an underground mining operation could be underestimated by 25%-48% if the algorithm ignores stope layout orientation.

Gel fire suppressants for controlling underground heating

One of the major safety issues in coal mining is heatings and the resultant spontaneous combustion in underground coal mines. CSIRO researchers have developed a number of polymer gels suitable for controlling beatings in coal mines. These gels were developed to meet strict selection criteria including easy preparation, no or low toxicity, controllable gelation time, adaptable to mine water chemistry, adjustable viscosity, relatively long gel life, thermally and chemically stable and low cost. The HPAM-Aluminum Citrate gel system was identified to be the most favourable gel system for fire suppression in under- ground coal mines. These gels can be applied to the areas undergoing coal heating or gas leakage at a controllable gelation time and impermeable gel barriers can be formed in the areas to block ingress of air.

The flocculation research on treating suspended solids contained mine drainage through goaf

Mine drainage could be filtered and purified through goaf. This innovative technique shows merits, such as high treatment efficiency, remarkable economic benefit and extensive wastewater recycle use. However, it was detected that capacities of purifying mine drainage for goaf were decreased after a period of application. As a result, the effluent could not meet the standard of recycle water. To solve the problem, coagulant was considered to add into mine drainage reducing its high turbid degrees to certain level. After the preliminary flocculation treatment, mine drainage was piped into goaf to purify. In this way, the load of goaf was eased up. Its usage time was also prolonged. Therefore, this paper carried out the coagulation-flocculation jar test for mine drainage to discuss the flocculation parameters. By the experiment, 10 % iron trichloride is selected from four inorganic coagulants as the optimum coagulant. The optimum dose, PH value and sedirs6-7 and 25 min. Velocity mentation time are respectively 2 mL per 800 mL Wastewater gradient G during the process of mixing and reaction is 696 .And the value of GT is 6.264 × 10^5. The values of G and GT will supply the basis for the design of flocculation pool in the project. The flocculation parameters will be significant for the reference of practice.

Numerical Analysis on Displacement Law of Discontinuous Rock Mass in Broken Rock Zone for Deep Roadways

On the basis of the characteristics of broken rock zone, using the program of "discontinuous deformation analysis(DDA)", the changing law of influential factors of discontinuous rock mass in large broken rock zone was researched quantitatively for the first time. Based on the results of computation, the concept of "key part"of roadways and its stability criterion were brought forward, and it was pointed out that in inclined coal and rock seams the"key parts"of roadways are the upper side and the floor of surrounding rocks, especially the former.

Transient Intersubband Optical Absorption in Double Quantum Well Structure

The microscopic equations of motion including many-body effects are derived to study the intersubband polarization in the double quantum well structure induced by an ultrafast pumping infrared light. Based on the selfconsistent field theory, the transient probe absorption coefficient is calculated. These calculations are beyond the previous steady-state assumption. Transient probe absorption spectra are calculated under different pumping intensity and various pump probe delay.

Optical Conductivity of Impurity-Doped Parabolic Quantum Wells in an Applied Electric Field

The optical conductivity of impurity-doped parabolic quantum wells in anapplied electric field is investigated with the memory-function approach, and the analyticexpression for the optical conductivity is derived. With characteristic parameters pertaining toGaAs/Ga_(1-x)Al_xAs parabolic quantum wells, the numerical results are presented. It is shown that,the smaller the well width, the larger the peak intensity of the optical conductivity, and the moreasymmetric the shape of the optical conductivity; the optical conductivity is more sensitive to theelectric field, the electric Geld enhances the optical conductivity; when the dimension of thequantum well increases, the optical conductivity increases until it reaches a maximum value, andthen decreases.