水电站压力隧洞及地下压力钢管排水系统设计

广州抽水蓄能电站二期工程压力隧洞及高压岔管均采用钢筋混凝土衬砌结构,按限制裂缝开展宽度进行设计。由于混凝土的透水性及地层中存在的地下压力渗水对电站永久性建筑物的危害及不安全性,以及压力钢管抵抗外压力远小于内压力的特性,故有必要对这些渗水进行工程处理。本文即是简要介绍本工程排水系统的设计。

地下压力箱涵背水面堵漏技术应用研究

伸缩缝渗漏是地下箱涵长时间运行过程中易出现的通病。利用停水检修期在箱涵内部对伸缩缝进行聚氨酯化学灌浆,是箱涵渗漏维修的常用手段,且效果较好,但使用该材料对高水压运行状况下的箱涵底部背水面进行渗漏处理,国内尚无先例。本文结合石津干渠沧州支线压力箱涵渗漏案例,阐述了该工艺的应用,并结合实施效果,总结了该技术的可行性与局限性,以期为后续类似工程施工提供指导借鉴。

地下压力非光滑钢管弹性稳定优化研究

为避免目前火(核)电厂地下压力非光滑钢管选用水平布置槽钢为刚性环设计的不足,提出了采用竖向布置的槽钢压力刚性环的新方法,建立了地下压力非光滑钢管弹性稳定优化设计的数学模型及采用竖向布置的槽钢作为刚性环的方案,并结合工程实例,对循环水地下压力非光滑钢管进行弹性稳定优化研究,结果表明采用竖向布置的槽钢为刚性环,选用投资最小的刚性环型号、刚性环间距即采用"经济间距经济环"优化设计方案,与原"小环小间距"计方案相比,技术可靠、经济效益显著。

地壳中重力、构造力和构造附加压力的力学基础

迄今为止,地质作用的深度通常是用压力除以密度来计算的。这种方法只在假设岩石处于静止的液体状态下才是正确的(Heim,1878)。然而,实际上从浅部地壳直至地慢深处的岩石都是固体状态而不是液体状态,且粘性系数随深度递增。实测数据表明地下水平压应力总是大于垂直压应力,说明构造力在量值上超过重力。所以,在地壳中进行地质作用深度的测算必须把岩石看作是固体并依据固体物理理论,在吕古贤等提出地质作用的深度测算方法正好考虑到了这一情况。

淮水北调工程固镇站埋地压力输水结构型式比选

本文介绍了淮水北调工程固镇站埋地压力输水结构型式比选及输水地下箱涵设计特点,可供类似长距离大流量耐压输水工程借鉴。

我国地下储气(氢)井检测技术进展综述

储气井广泛用于汽车加气站储存压缩气体。在对储气井相关文献调研的基础上,结合最新的科研成果和检验工程实践,对储气井的主要检验检测技术、法规标准现状进行了讨论、梳理和总结。对储氢井技术发展情况和检验检测技术难点以及可行的检测技术进行了分析探讨,提出了关于储氢井检验检测技术的建议。

双河口水电站的发电引水系统设计

双河口水电站是一座以发电为主的山区水电建设项目,采用坝后式引水开发。水电站总装机容量120MW,装机3台。设计结合山区起伏地形地质条件,对发电引水隧洞的布置、洞线调整优化、岔支管的布置形式进行了深入的研究比选,确定了紧凑、合理的引水系统布置格局。充分结合调保计算及有限元专题研究,进行岔管体形优化与建筑结构设计,使其设计成果更准确、合理、可靠。

Detection and treatment of water inflow in karst tunnel：A case study in Daba tunnel

In a karst tunnel, fissures or cracks that are filled with weathered materials are a type of potential water outlet as they are easily triggered and converted into groundwater outlets under the influence of high groundwater pressure. A terrible water inrush caused by potential water outlets can seriously hinder the project construction. Potential water outlets and water sources that surrounding the tunnel must be detected before water inflow can be treated. This paper provides a successful case of the detection and treatment of water inflow in a karst tunnel and proposes a potential water outlet detection(PWOD) method in which heavy rainfall(>50 mm/d) is considered a trigger for a potential water outlet. The Daba tunnel located in Hunan province, China, has been constructed in a karst stratum where the rock mass has been weathered intensely by the influence of two faults. Heavy rain triggered some potential water outlets, causing a serious water inrush. The PWOD method was applied in this project for the treatment of water inflow, and six potential water outlets in total were identified through three heavy rains. Meanwhile, a geophysical prospecting technique was also used to detect water sources. The connections between water outlets and water sources were identified with a 3-D graphic that included all of them. According to the distribution of water outlets and water sources, the detection area was divided into three sections and separately treated by curtain grouting.

Review of roadway control in soft surrounding rock under dynamic pressure

The basic characteristics of the soft rock roadway under the dynamic pressure are analyzed. At the same time, the three fundamental approaches for controlling the surrounding rock are proposed, which are improving the surrounding rock strength, lowering the rock mass stress and selecting the reasonable supporting technology. The research results are elucidated, including the distribution of the surrounding rock plastic zone, the movement and damage of the surrounding rock under the dynamic pressure, controlling the floor heave through reinforcing the roadway walls and corners, the new route to develop the roadway metal supporting technique, the key theory and technique for the bolt supporting in the coal roadway, the performance and prospect of the ZKD high water content quick setting material, and so on. Finally, some personally views are put forward about the roadway metal supporting, bolt supporting, new material and the stress relief under the high stress condition.

Three-dimensional upper bound limit analysis of underground cavities using nonlinear Baker failure criterion

A generalized nonlinear Baker failure criterion is employed with the upper bound limit analysis to study the surrounding rock stability of underground cavities. A three-dimensional(3D) failure mode is established by extending the two-dimensional(2D) failure mode, which offers an upper bound expression of the surrounding rock pressure. This method is validated with a series of examples before the influence of four parameters of scale parameter, curvature parameter, shift parameter and lateral pressure coefficient, on the surrounding rock pressure is analyzed. According to these results, failure ranges of the underground cavities are determined. The following conclusions are reached:(1) the proposed approach is more accurate to predict surrounding rock pressure than the Mohr-Coulomb failure criterion;(2) the surrounding rock with large scale parameter, curvature parameter, shift parameter, and lateral pressure coefficient can lead to a more stable underground cavity;(3) the failure range in 3D mode can be predicted according to the upper bound solutions.

Effects of atmospheric pressure fluctuations on hill-side coal fires and surface anomalies

This paper presents numerical studies on the effects of atmospheric pressure fluctuations on hill-side coal fires and their surface anomalies. Based on the single-particle reaction–diffusion model, a formula to estimate oxygen consumption rate at high temperature controlled by oxygen transport is proposed.Daily fluctuant atmospheric pressure was imposed on boundaries, including the abandoned gallery and cracks. Simulated results show that the effects of atmospheric pressure fluctuations on coal fires and surface anomalies depend on two factors: the fluctuant amplitude and the pressure difference between inlet(s) and outlet(s) of the air ventilation system. If the pressure difference is close to the fluctuant amplitude, atmospheric pressure fluctuations greatly enhance gas flow motion and temperatures of the combustion zone and outtake(s). If the pressure difference is much larger than the fluctuant amplitude, atmospheric pressure fluctuations exert no impact on underground coal fires and surface anomalies.

A new failure mechanism for deep cavity and upper bound solution of supporting pressure

The investigation of supporting pressure is of great significance to the design of underground structures.Based on the kinematical approach of limit analysis,an improved failure mechanism is proposed,and the supporting pressure is investigated for deep buried cavity.Three failure mechanisms are first introduced according to the existing failure mechanisms of geotechnical structures of limit analysis.A comparison with respect to the optimal failure mechanisms and the upper bound solutions provided among these three mechanisms are then conducted in an attempt to obtain the improved failure mechanism.The results provided by the improved failure mechanism are in good agreement with those by the existing method,the numerical solution and field monitoring,which demonstrates that the proposed failure mechanism is effective for the upper bound analysis of supporting pressure.

Finite layer and triangular prism element method to subsidence prediction and stress analysis in underground mining

The application of the finite layer & triangular prism element method to the 3D ground subsidence and stress analysis caused by mining is presented. The layer elements and the triangular prism elements have been alternatively used in the numerical simulation system, the displacement pattern, strain matrix, elastic matrix, stiffness matrix, load matrix and the stress matrix of the layer element and triangular prism element have been presented. By means of the Fortran90 programming language, a numerical simulation system based on finite layer & triangular prism element have been built up, and this system is suitable for subsidence prediction and stress analysis of all mining condition and mining methods. Comparing with the infinite element method, this approach dramatically reduces the size of the set of equations that need to be solved, and greatly reduces the amount of data preparation required. It not only saves the internal storage, and the computation time, but also decreases the cost.

Numerical analysis of stability for mined-out area in multi-field coupling

There were differences between real boundary and blast hole controlling boundary of irregular mined-out area in underground metal mines. There were errors in numerical analysis of stability for goaf, if it was analyzed as regular 3D mined-out area and the influence of coupling stress-seepage-disturbance was not considered adequately. Taking a lead zinc mine as the background, the model was built by the coupling of Surpac and Midas-Gts based on the goaf model precisely measured by CMS.According to seepage stress fundamental equations based on the equivalent continuum mechanical and the theory about equivalent load of dynamic disturbance in deep-hole blasting, the stability of mined-out area under multi-field coupling of stress-seepage-dynamic disturbance was numerically analyzed. The results show that it is more consistent between the numerical analysis model based on the real model of irregular 3D shape goaf and the real situation, which could faithfully reappear the change rule of stress–strain about the surrounding rock under synthetic action of blasting dynamic loading and the seepage pressure. The mined-out area multi-field coupling formed by blasting excavation is stable. Based on combination of the advantages of the CMS,Surpac and Midas-Gts, and fully consideration of the effects of multi-field coupling, the accurate and effective way could be provided for numerical analysis of stability for mined-out area.

Inversion of the Volumetric Strain of Aquifer According to the Tidal Effect of Groundwater in North China

The change of the confined aquifer level reflects the pore pressure change,and the pore pressure change of the aquifer is closely related to the aquifer pressure. This paper uses the tidal response of the well water level data in the North China region to calculate the tidal factor of each well and extract the effective water trend information. Then,the volumetric strain of an existing confined aquifer well in the North China region is inverted,and the contour maps are plotted on a half-year scale from 2009 to 2012. Results show that it can reflect the state of stress and strain in deep crust to a certain extent in the North China region.

3D-FSM·DDM IBEM numerical system of multi-medium

Based on the idea of the developed 3D-FSM.DDM boundary element method, the field with muti-medium was formulized firstly, then connected at the interface of two fields according to the continuous conditions of stress and displacement, after that, a boundary value problem with unified model was formed and solved. Ultimately, an applied numerical simulation system was developed. It was compared with the model having analytical solution for verifying the applicability and the calculating precision.

Application Study on Correction Method for Lag of Water Level Response to Earth Tide and Atmospheric Pressure

The water level in a deep well instantly responds to the earth’s tide and atmospheric pressure, and varies accordingly, not only in terms of amplitude but also in the phase lag. Therefore, phase lag correction is used in analyzing digital groundwater observation data in eastern China. Calculation results presented by the authors in this paper show that the correction method is effective in the identification of anomalous changes for short-term seismic precursors. The correction method can also be applied to the processing of observed deformation and tilt data.

Estimation of Antropogenenic Pressure on Landscapes of Oasises （on Example of Mid and Lower Part of Zarafshan River）

The paper discusses about anthropogenic pressure classification system on landscape oasises. As a result, based on designed criteria rates a thematic map titled ＂Anthropogenic pressure and its consequences on landscapes oasises of mid and lower part of Zarafshan River Basin＂ was developed. The thematic map depicts realthionship between ecological conditions and population diseases along various landscape oasises of the Zarafshan river valley.

Clay Minerals Properties as Downhole Formation Pressure Indicator

The successful estimation of formation pressures （or formation pore gradient） is fundamental and the basis for many engineering works including drilling and oilfield development planning. Common log data are used for formation pressure calculation. Modern techniques for pressure prediction have several disadvantages, notably, incorrect account of the downhole nonsteady thermal field and clay mineral composition. We propose a way to overcome listed shortcomings： a technique for thermal field proper account while formation pressure estimation and a petrophysical model, which reflects relationships between clay minerals composition and rock properties, derived from log data.

“直供”投资不是好办法(摘要)

现行的基本建设投资分配体制中,有一类“直供项目”。各部分配投资,由中央财政出钱建厂,建成后生产和收入归地方。这个办法花钱向上报,不够向上要,是典型的“吃大锅饭”的办法。浙江长广矿区七号井,是煤炭部的一个直供项目。设计能力年采煤四十五万吨,概算投资四千零二十六万元,一九七○年开始建设,施工十年,花去投资一千二百六十一万元。