Simulation of Underground Reservoir Stability of Pumped Storage Power Station Based on Fluid-Structure Coupling

Based on global initiatives such as the clean energy transition and the development of renewable energy,the pumped storage power station has become a new and significant way of energy storage and regulation,and its construction environment is more complex than that of a traditional reservoir.In particular,the stability of the rock strata in the underground reservoirs is affected by the seepage pressure and rock stress,which presents some challenges in achieving engineering safety and stability.Using the advantages of the numerical simulation method in dealing deal with nonlinear problems in engineering stability,in this study,the stability of the underground reservoir of the Shidangshan(SDS)pumped storage power station was numerically calculated and quantitatively analyzed based on fluid-structure coupling theory,providing an important reference for the safe operation and management of the underground reservoir.First,using the COMSOL software,a suitablemechanicalmodel was created in accordance with the geological structure and project characteristics of the underground reservoir.Next,the characteristics of the stress field,displacement field,and seepage field after excavation of the underground reservoir were simulated in light of the seepage effect of groundwater on the nearby rock of the underground reservoir.Finally,based on the construction specifications and Molar-Coulomb criterion,a thorough evaluation of the stability of the underground reservoir was performed through simulation of the filling and discharge conditions and anti-seepage strengthening measures.The findings demonstrate that the numerical simulation results have a certain level of reliability and are in accordance with the stress measured in the project area.The underground reservoir excavation resulted in a maximum displacement value of the rock mass around the caverns of 3.56 mm in a typical section,and the safety coefficient of the parts,as determined using the Molar-Coulomb criterion,was higher than 1,indicating that the project as a whole is in a stable state.

Key rock mechanical problems of underground powerhouse in Shuibuya hydropower station

The complicated rock structures and the stability of surrounding rocks of the underground powerhouse were the key rock mechanical problems in Shuibuya hydropower station.In order to overcome the related rock mechanical problems encountered during its construction,a comprehensive research was carried out for the underground powerhouse in Shuibuya hydropower station based on a detailed geological survey.It covers the investigations on the initial in-situ stress distribution features,rock mechanical properties,engineering rock mass classifications by different methods,numerical modeling for stability and support analysis,proper measures for rock excavation and support.The results show that the rock excavations of the underground powerhouse under the given geological conditions can be controlled effectively.Some measures,suggested by the designers,are proved to be rational and effective.These measures mainly consist of:(1) the soft rock replacements by concrete in local area below the crane beam,(2) the shotcrete and reinforcement by rock bolts and anchor cables in surrounding rocks,and (3) 2 m concrete placement on the rock bench between adjacent tailrace tubes.The engineering practice shows that the treated surrounding rocks have a good overall stability.The deformation behaviors observed by safety equipments are within the designing limits.The research conclusions on the related rock mechanical problems,prior to the underground powerhouse excavations,are reliable.

Measures for controlling large deformations of underground caverns under high in-situ stress condition--A case study of JinpingⅠhydropower station

The Jinping I hydropower station is a huge water conservancy project consisting of the highest concrete arch dam to date in the world and a highly complex and large underground powerhouse cavern. It is located on the right bank with extremely high in-situ stress and a few discontinuities observed in surrounding rock masses. The problems of rock mass deformation and failure result in considerable challenges related to project design and construction and have raised a wide range of concerns in the fields of rock mechanics and engineering. During the excavation of underground caverns, high in-situ stress and relatively low rock mass strength in combination with large excavation dimensions lead to large deformation of the surrounding rock mass and support. Existing experiences in excavation and support cannot deal with the large deformation of rock mass effectively, and further studies are needed. In this paper, the geological conditions, layout of caverns, and design of excavation and support are first introduced, and then detailed analyses of deformation and failure characteristics of rocks are presented. Based on this, the mechanisms of deformation and failure are discussed, and the support adjustments for controlling rock large deformation and subsequent excavation procedures are proposed. Finally, the effectiveness of support and excavation adjustments to maintain the stability of the rock mass is verified. The measures for controlling the large deformation of surrounding rocks enrich the practical experiences related to the design and construction of large underground openings, and the construction of caverns in the Jinping I hydropower station provides a good case study of large-scale excavation in highly stressed ground with complex geological structures, as well as a reference case for research on rock mechanics.

Precision blasting excavation of rock face beam in underground hydropower station under complex geological conditions

To deal with the construction difficulties of Xiangjiaba underground hydropower station,such as complex geological conditions,narrow rock bench,high loading,high quality requirements and urgent time limit,the project adopted the concept of precision blasting.The explosive energy and rock mass fragmentation were well controlled by taking reasonable excavation sequence,designing steel pipe drilling frame,the additional techniques of double layer smooth blasting,evenly micro charge,staggered arrangement of boreholes and pre-stressed anchors.These technologies ensured the excavation quality of the rock face beam,achieving successful blasting results:Semi hole ratio was 100%in Ⅱ surrounding rock,99.2%in Ⅲ surrounding rock and 90%~ 97.3%in Ⅳ surrounding rock;underbreak was avoided and the average backbreak was only2.9 cm;the unevenness was 0 ~ 4 cm;the influence depth of blasting and unloading was 0.2 ~ 0.7 cm.

Rule Based Collector Station Selection Scheme for Lossless Data Transmission in Underground Sensor Networks

There are fundamentally two different communication media in wireless underground sensor networks. The first of these is a solid medium where the sensor nodes are buried underground and wirelessly transmit data from underground to aboveground. The second is an underground medium such as tunnel, cave etc. and the data is transmitted from underground to the aboveground through partially solid medium. The quality of communication is greatly influenced by the humidity of the soil in both environments. The placement of wireless underground sensor nodes at hard-to-reach locations makes energy efficient work compulsory. In this paper, rule based collector station selection scheme is proposed for lossless data transmission in underground sensor networks. In order for sensor nodes to transmit energy-efficient lossless data, rulebased selection operations are carried out with the help of fuzzy logic. The proposed wireless underground sensor network is simulated using Riverbed software, and fuzzy logic-based selection scheme is implemented utilizing Matlab software. In order to evaluate the performance of the sensor network;the parameters of delay, throughput and energy consumption are investigated. Examining performance evaluation results, it is seen that average delay and maximum throughput are accomplished in the proposed underground sensor network. Under these conditions, it has been shown that the most appropriate collector station selection decision is made with the aim of minimizing energy consumption.

The Use of Underground Metro Stations and Tunnels as Protective Structures in Case of Nuclear Emergencies

This paper discusses the use of Underground Metro stations and tunnels as protective structures in case of nuclear emergencies. Six lines are taken as a case study to investigate the use of their underground stations and tunnels. The research explains the structural design of Underground Metro and the necessary needs for hidden people inside Underground Metro used as shelters. The research investigates the calculations of the number of hidden persons inside Underground Metro used as shelters. A field study has been conducted to an Underground Metro station to detemaine the peaceful use and the emergency use of all basements of the station. Also, the field study aims to determine the existing spaces and the needed spaces of the Underground Metro station to dual--used as a nuclear shelter. Three Underground Metro stations have been selected and a field study has been conducted to determine the usages of these basements, the planning, general and design features for each one of them, and whether they can be used as protective structures for citizens in emergencies. These basements were compared for their protective factors. Also, their capacities for sheltering were calculated.

An experimental study on fire characteristics of urban complex underground space based on BIM

Compared with the space on the ground,if there is a fire in the urban complex underground space,the loss will be greatly harmful.In addition,the complex underground space is usually connected with other large space areas and densely populated.Once a fire occurs in the complex underground space,it will cause huge property losses and casualties.In order to reduce the risk of fire,it is necessary to deeply understand the development rules and characteristics of fire in the complex underground space of the city.This article has mainly carried on the following work:(I)A particularly complex model of the multi‐storey subway station was built.On this basis,three groups of comparative experiments were conducted to study the effects of fire power,fire location and smoke control system on fire development,and the conclusion that fire location is the most important factor for fire development was obtained;(II)In order to explore the entire space fire and the local space fire,CFD(Computational Fluid Dynamics)is used to build a large‐size fire model and a small‐size fire model respectively;(III)Multiple detector data as temperature slices were built,and it is expected to make full use of the simulation data to deduce the important index of fire location in the early stage of fire.All of the works in this paper will provide reference experimental data for the prevention and firefighting of a sudden fire in the complex underground space.

地铁入口空间布局对室内空气质量的影响研究

城市地铁地处繁华地区,结构封闭,周边环境污染源较多,室内易积累污染物。本研究重点关注地铁口空间布局对室外颗粒物进入的影响,在调研中选取地铁站入口方向、顶棚形态、入口高宽比3个形态指标作为影响因子,经过实测验证CFD模型的可行性后,选择RNG k-ε模型模拟不同风速下各地铁口形态的室内污染情况。结果表明:(1)侧向比正向入口颗粒拦截率高一倍;(2)入口高宽比小于1∶1时入口宽度越大,地铁站整体空气质量越好;(3)顶棚形态对室内颗粒物的消减排列为:斜顶>平顶>无顶;(4)地铁口空间形态对不同直径的颗粒拦截效果不同。形态设计可以改善站内颗粒物进入情况,通过空气对流、回流减少室外污染物的直接灌入。

地铁双线隧道下穿既有车站冻结加固冻胀控制措施

针对城市长距离大断面地下空间冻结工程的冻胀特性问题,依托上海地铁18号线国权路站双线隧道下穿既有车站冻结工程,基于热力耦合方程,利用有限元软件建立三维数值模型,结合室内试验所得物理参数,研究该工程的冻胀位移场演化规律,并探究错峰冻结、调整盐水温度等措施对冻胀位移场的影响规律。在本试验条件下,研究结果表明:①冻胀引起的车站底板变形主要发生于积极冻结期;双线隧道同时冻结模式下,冻结45 d时车站底板竖向位移量达到冻结90 d时竖向位移量的77.72%。②冻结90 d时,错峰冻结工况下车站底板竖向位移量较双线隧道同时冻结时减小了7.7%,表明错峰冻结避免了同一时间段内的冻胀叠加效应,一定程度上降低冻胀效应。③冻结90 d时,调整盐水温度工况下车站底板竖向位移量较温度调控前减小34.2%;表明调整盐水温度可控制冻土扩展速率,有效降低冻胀效应。实际工程中,采用错峰冻结、调整盐水温度等措施协同控制冻胀,车站底板最大竖向位移为25.41 mm;数值模拟所得车站底板抬升规律与实测数据基本一致,有效指导了工程施工。

地下泵站进水流道数值模拟与方案优化

以典型地下泵站的进水流道为研究对象,建立数值仿真模型,分析设计方案的水力特性及存在不足,并给出优化方案.研究结果表明:在原方案中,外侧水泵进水管入口中心和圆洞出口中心的连线与来流方向的夹角达到70°,水流大角度偏转,并在进水管入口出现脱流现象,水头损失系数达到2.31~2.44,水泵进水管出口的流速分布均匀度为95.09%~96.80%,速度加权平均角为86.51°~87.41°,原方案的圆洞突扩进入压力罐,然后突缩进入水泵的进水管,且压力罐内无任何导流措施,致使局部流道产生了较大的水头损失;优化方案提出了“集管+岔管”的分流措施,通过2个60°弯头实现水流流向的偏移,平面和垂直方向均没有突扩或突缩结构,水头损失系数减小至0.93~1.07,优化方案不仅改善了流道的水力性能,也避免了开挖、衬砌压力罐.研究结果可为类似地下泵站进水流道设计提供一定依据.

基于易损性分析的地铁车站抗震韧性评价方法

研究目的:地铁车站结构由于深埋于地下,一旦发生地震破坏,防灾救护、灾后修复将非常困难,而且将会造成巨大的经济损失以及人员伤亡。提高地铁车站的抗震韧性能力是可持续发展的重要保障。本文提出一种简单实用的地铁车站抗震韧性评价方法,用于评估不同场地条件下常见典型地铁车站的抗震韧性,为地铁车站的抗震韧性提升提供决策依据。研究结论:(1)本抗震韧性评价方法,不仅考虑了结构部分,还考虑了非结构构件,更为合理和真实;(2)本文提供的地铁车站结构抗震易损性曲线,分别考虑了地下两层单跨、两层双跨、两层三跨在Ⅰ、Ⅱ、Ⅲ类场地的情况,更为全面和实用;(3)随着地铁车站跨数的增加,不同损伤状态下的超越概率减小,车站趋于安全;随着地层从Ⅰ类场地降低到Ⅲ类场地,不同损伤状态下的超越概率变大,车站趋于危险;(4)本研究成果可以用于地铁车站的抗震韧性评估。

地下综合枢纽换乘空间设施布局优化设计研究——以北京城市副中心站为例

随着城市交通出行需求日益增加以及对城市交通功能的再认识,多线换乘、功能复合的轨交枢纽建设进入高峰期。导向标识、商服设施、交通设施布局的合理性很大程度影响了客流组织效能和通行效率,同时枢纽空间的复杂性增大了设施布局的难度。文章以北京城市副中心站为例,采用Depthmap和Anylogic双重仿真模拟的方法定性、定量分析其换乘空间设施布局和客流组织情况,针对性提出优化策略并加以验证,为地下枢纽科学合理的设施布局和发展提供解决思路和理论支持。

上海轨道交通车站暗挖技术应用与探索

[目的]上海的城市轨道交通经过多年发展,现已面临极其复杂和严苛的工程建设环境,地下车站大开挖导致的交通拥堵、房屋拆迁和管线搬迁等问题已逐渐成为社会舆论的焦点。针对地铁建设与周边环境的冲突与矛盾,上海轨道交通通过持续科技攻关和试验论证,提出了多项软土地层暗挖技术。[方法]介绍了暗挖技术的发展历史和应用现状;基于上海轨道交通建设的特点,介绍了上海轨道交通暗挖技术中顶管法、冻结法和管棚法的具体内涵及应用情况;探讨了大断面顶管法、超长特大断面管幕法、超浅埋大断面冻结法和束合管幕法等新型暗挖车站建造技术的研究和试点应用情况。[结果及结论]上海轨道交通暗挖技术主要包括盾构法、顶管法、冻结法、管棚法以及其他特殊暗挖工法,已广泛应用于地下区间工程、区间联络通道工程、车站附属结构工程以及车站局部改造工程等;新型暗挖车站建造技术能够有效应对新条件下上海轨道交通建设的特点和面临的挑战。

砂卵石地层浅埋地铁车站暗挖施工关键技术

研究目的:针对富水砂卵石地层地铁车站明挖法施工面临的道路交通问题,本文依托成都富水砂卵石地层首次采用暗挖法施工地铁车站的成功案例,对暗挖法施工关键工艺开展研究,指明了暗挖导洞设置及其开挖时序、地层超前预加固方式、初期支护类型、永临结合钢管柱以及拱形盖板扣拱等关键工艺,明确了富水砂卵石地层浅埋大跨地铁车站首次采用暗挖法施工的可行性。研究结论:(1)基于“化整为零”的思路,借助大刚度管幕超前支护,明确了导洞设置原则,采用多导洞法实施钢立柱与盖板(顶板)后,可按盖挖法理念完成超浅覆土下的地铁车站暗挖施工;(2)浅覆土管幕打设精度与地层扰动控制是富水砂卵石地层沉降控制的关键,应遵循“精准定位、及时纠偏,欠土顶进、严控超挖,先低速后匀速”的基本原则;(3)基于初期支护主要以被动承载为主,格栅钢架经济性好、施工方便,喷混后抗弯刚度增幅将近8倍,且大于工字钢喷混后等效抗弯刚度,宜采用格栅钢架;(4)顶部预埋倒L形钢板的“蛇形”中立柱,可实现两侧衬砌结构的有效连接与水平向有效传力,液压反循环钻机可满足小净空条件下高精度永临结合钢管柱施作需要;(5)本研究结论可为类似地层暗挖法车站施工提供借鉴与参考。

考虑碳排放的地下洞室群施工资源动态均衡优化

在中国“双碳”目标的背景下,持续推进地下洞室群等大型工程施工快速向低碳、绿色方向转型是当前面临的焦点问题。为了保证地下洞室群施工资源合理配置,实现绿色低碳施工,提出了一种衡量施工期碳排放均匀程度的指标“碳熵”,结合“资源熵”作为资源均衡的度量,建立了考虑碳排放和资源配套施工的资源均衡优化模型,并设计了一种内点算法进行求解;在此基础上构建了考虑施工进度延误条件下的资源动态优化流程,以确保发生风险事件后施工资源配置能得到及时优化与调整。乌东德水电站工程实例应用表明:该模型准确有效,可以提高资源总体均衡程度,降低施工期的资源投入峰值和碳排放峰值,从而提高资源配置效率。

地铁车站出入口暗挖工程专项施工技术

以实际工程为背景,研究地铁车站出入口暗挖工程关键技术,包括施工工艺流程、安全施工保障措施以及监测监控等方面。采用矿山法作为主要施工手段,严格按照“管超前、严注浆、短进尺、强支护、快封闭、勤量测”的十八字方针进行施工,以确保工程的高效性和安全性。结合现代化监测技术,对施工全过程进行实时监控,及时调整施工参数,确保施工质量和安全。通过工程实例,验证了所采用技术方案的可行性和有效性,并提出了进一步优化施工技术的建议。

基于POI的TOD项目设计策略研究

POI是“Point of Interest”的缩写。每个POI包含四方面信息,名称、类别、坐标、分类,文章拟通过对地面空间和地下空间两个维度的用地构成、建筑类型与使用功能的研究分析,尝试探索基于POI的旧城核心区地铁站出入口设置的量化设计方法。文章通过文献研读、类比分析等研究手段,对国内外地铁站出入口设置进行了梳理与分析,弥补了旧城核心区地铁站出入口量化设置研究的理论空白,为国内类似项目提供了一定的设计研究素材。

城市地铁车站地下空间绿色建筑设计方法研究

为了降低城市地铁车站地下空间绿色建筑的全年总能耗占比,提出一种绿色建筑设计方法,包括采光设计、节地设计和环保设计。采光设计运用技术引入自然光,并通过手动照明补偿不足;节地设计采用垂直布局减少占地面积;环保设计利用BIM技术实现高质量环保建筑。实验结果表明,该设计方法可将年度总能耗占比降至83.2%,满足预期标准,优化了城市地铁车站地下空间绿色建筑的设计方法,为绿色建筑的可持续发展提供了新思路。

合肥市地下两层标准车站主体结构设计分析

文章结合合肥市2~7号线地下两层标准车站主体结构设计情况,从主要结构构件尺寸、配筋率、梁柱节点、诱导缝等方面进行总结,在统计已经成功实施的11座地下两层标准车站主体结构设计参数的基础上,根据站台宽度和结构的不同,从板、墙、梁、柱等主要受力构件的尺寸和配筋率等方面进行统计分析,得出规律和指导性指标,并对部分细节做法提出了完善建议。

天津某地铁车站深基坑工程监测数据分析

为了研究深基坑开挖变形规律及变形控制要点,以天津某地铁车站深基坑工程为研究对象,对深基坑施工全过程监测数据进行了分析,重点研究了施工过程中地下连续墙水平位移、支撑轴力、地表沉降、周边建筑物等实测数据随各施工工序和时间的变化规律,并对南侧地下连续墙墙体水平位移和建筑物变形超标的原因进行了详细分析。实测数据表明:地下连续墙施工及降水试验期间地表及建筑物沉降明显;除南侧地下连续墙体水平位移和建筑物变形超标外,其他各项变形数据均小于设计允许值;地下连续墙的施工质量对墙体水平位移有显著影响;建筑物沉降比地表沉降更加敏感;基坑开挖过程中除监测外,还应加强对墙体质量、渗漏水等情况的巡查。