發(fā)布時(shí)間：2019-06-06 06:37

【摘要】：在地下空間的大規(guī)模建設(shè)開發(fā)、城市極端降水事件頻繁發(fā)生情況下,地下空間遭受水侵風(fēng)險(xiǎn)極高,地下空間水侵災(zāi)害事件已不容忽視。地下空間出入口階梯是泛濫河水或暴雨積水入侵時(shí)被困人員撤離的關(guān)鍵通道,已成為威脅行人安全撤離的風(fēng)險(xiǎn)極高的區(qū)域。為了探討地下空間水侵災(zāi)害時(shí)被困人員疏散時(shí)的安全性,本文針對(duì)性地研究了水侵災(zāi)害時(shí)用于行人行走的階梯上水流的水力特性及人體(簡(jiǎn)化為柱體)的繞流特性,主要內(nèi)容如下： 首先,總結(jié)了階梯摻氣水流的類型和水流摻氣的原因,將摻氣水流劃分為含清水層的摻氣水流和不含清水層的摻氣水流,分析了摻氣水流的運(yùn)動(dòng)規(guī)律,歸納了不同數(shù)量水氣交界面的摻氣水流的摻氣運(yùn)動(dòng)機(jī)理,并根據(jù)水流摻氣的相關(guān)理論,推導(dǎo)出了兩個(gè)氣相線(面)源(兩個(gè)水氣交界面)摻氣濃度分布的基本形式及水力特性參數(shù)的計(jì)算方法。 其次,根據(jù)選定的地下空間出入口形態(tài)及水力學(xué)模型試驗(yàn)原理,設(shè)計(jì)制作出帶中間休息平臺(tái)的地下空間出入口階梯綜合試驗(yàn)平臺(tái),試驗(yàn)研究了地下空間受洪水入侵災(zāi)害時(shí)含休息平臺(tái)的階梯水流的水力特性,得到了階梯水流流場(chǎng)、初始摻氣點(diǎn)、摻氣濃度分布、水氣混合速度及階梯平臺(tái)挑流等特性,并驗(yàn)證了不含清水層的兩個(gè)水氣交界面摻氣水流摻氣濃度分布的基本形式。 再次,根據(jù)試驗(yàn)結(jié)果和數(shù)值模型的相關(guān)理論,構(gòu)建并驗(yàn)證了階梯水流流場(chǎng)數(shù)值模擬模型,并基于數(shù)值模型的靈活性和可變性,模擬了休息平臺(tái)、階梯坡度和階梯形態(tài)對(duì)水流流場(chǎng)的影響,分析了有無(wú)休息平臺(tái)、不同階梯坡度和不同階梯形態(tài)下階梯水流流態(tài)、流速分布及其對(duì)被困人員的安全撤離的影響。 最后,提出了復(fù)雜水流工況下突出自由液面的柱體繞流作用力的測(cè)量方法,制作出測(cè)量裝置,并通過三種方式驗(yàn)證了該裝置測(cè)力時(shí)的精度；簡(jiǎn)化人體繞流為柱體繞流,并考慮單人或多人同時(shí)撤離的不同情況,試驗(yàn)研究了單柱體在不同入侵水深和在階梯不同位置工況下、多柱體在不同的排列狀況下的繞流流場(chǎng)與水流作用力,并據(jù)此計(jì)算分析繞流阻力系數(shù)。 論文的創(chuàng)新點(diǎn)在于：針對(duì)階梯水流的高摻氣率、且在休息平臺(tái)后的挑流含有兩個(gè)水氣交界面的特點(diǎn),推導(dǎo)出含兩個(gè)氣相線(面)源(兩個(gè)水氣交界面)的摻氣水流濃度分布的基本形式,并結(jié)合試驗(yàn)數(shù)據(jù)進(jìn)行了驗(yàn)證；結(jié)合物理試驗(yàn)與數(shù)值模擬,研究了休息平臺(tái)、階梯坡度與階梯形態(tài)(直線型、90°轉(zhuǎn)彎L型與1800轉(zhuǎn)彎U型)對(duì)階梯水流水力特性的影響；針對(duì)復(fù)雜水流工況下突出自由液面的豎直及斜置柱體在恒定及非恒定水流工況下作用力的測(cè)量問題,提出并制作出相應(yīng)的測(cè)量裝置,且應(yīng)用于階梯上柱體繞流作用力的測(cè)量；試驗(yàn)研究了階梯上的單柱與多柱繞流特性,總結(jié)分析了階梯上柱體的繞流阻力系數(shù)。
[Abstract]:With the large-scale construction and development of underground space and the frequent occurrence of extreme precipitation events in cities, the risk of water invasion in underground space is very high, and the disaster event of water invasion in underground space can not be ignored. The entrance and exit ladder of underground space is the key channel for the evacuation of trapped people when flooding the river or heavy rain and water intrusion, and has become a very high risk area to threaten the safe evacuation of pedestrians. In order to explore the safety of evacuation of trapped people in underground space water invasion disaster, this paper studies the hydraulic characteristics of water flow on the ladder used for pedestrian walking during water invasion disaster and the flow characteristics of human body (simplified as cylinder). The main contents are as follows: firstly, the types of step aerated flow and the causes of aerated flow are summarized. The aerated flow is divided into aerated flow in clear water layer and aerated flow without clear water layer, and the movement law of aerated flow is analyzed. The aeration movement mechanism of aerated flow at different water-gas interface is summarized, and according to the related theory of flow aeration, The basic form of aeration concentration distribution of two gas line (surface) sources (two water-gas interface) and the calculation method of hydraulic characteristic parameters are derived. Secondly, according to the selected underground space entrance and exit shape and hydraulic model test principle, the underground space entrance and exit ladder comprehensive test platform with intermediate rest platform is designed and manufactured. The hydraulic characteristics of stepped flow with rest platform in underground space subjected to flood invasion are studied experimentally. the characteristics of stepped flow field, initial aeration point, aeration concentration distribution, water and gas mixing velocity and ladder platform flow are obtained. The basic form of aeration concentration distribution of two water-gas interface aerated flow without clear water layer is verified. Thirdly, according to the experimental results and the related theories of the numerical model, the numerical simulation model of stepped flow field is constructed and verified, and the rest platform is simulated based on the flexibility and variability of the numerical model. The influence of ladder slope and ladder shape on the flow field is analyzed, and the flow pattern, velocity distribution and its influence on the safe evacuation of trapped people with or without rest platform, different ladder slope and different ladder form are analyzed. Finally, the measurement method of the flow force around the cylinder protruding the free liquid level under complex flow conditions is put forward, and the measuring device is made, and the accuracy of the device is verified by three ways. The flow around the human body is simplified as the flow around the cylinder, and considering the different situations of single or multiple people evacuating at the same time, the single cylinder is tested and studied under different invasive water depths and different positions of the ladder. The flow field and flow force around the multi-cylinder under different arrangement conditions, and the resistance coefficient around the flow is calculated and analyzed. The innovation of this paper is that in view of the high aeration rate of stepped flow, and the flow carrying after the rest platform contains the characteristics of two water-gas interface. The basic form of aerated flow concentration distribution with two gas line (surface) sources (two water-gas interface) is derived and verified by the experimental data. Combined with physical test and numerical simulation, the effects of rest platform, ladder slope and ladder shape (linear, 90 擄turning L-shaped and 1800 U-shaped) on the hydraulic characteristics of stepped flow are studied. In order to solve the problem of measuring the vertical and oblique cylinder force of protruding free liquid level under constant and unstable flow conditions under complex flow conditions, the corresponding measuring device is put forward and made, and applied to the measurement of flow force around the cylinder on the ladder. The flow characteristics of single column and multi-column on the ladder are studied, and the flow resistance coefficient around the cylinder on the ladder is summarized and analyzed.
【學(xué)位授予單位】：浙江大學(xué)
【學(xué)位級(jí)別】：博士
【學(xué)位授予年份】：2014
【分類號(hào)】：TV131.3

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本文編號(hào)：2494143