真空管井复合降水技术应用研究
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摘要
随着城市建设的不断发展,地铁交通也日益迅速发展。在地铁建设过程中,如何处理好地下水是一大难题。北京地铁施工中,采用常规降水方法很难疏干上层滞水、弱透水层、饱和土体中的水及含水层界面残留水,施工带水作业严重,这给快速经济地进行隧道开挖、安全文明施工带来很大隐患,是目前地铁工程施工亟待解决的降水难题。本文针对北京地区地铁施工降水难题,将真空技术与成熟的管井降水技术有机结合,提出真空管井复合降水新方法,并完成了室内物理模拟试验、现场工程试验、现场测试、基本理论及工程设计研究。本课题研究成果无论在理论还是在工程应用上,都具有重大的意义。主要研究工作如下:
通过室内物理模拟试验和现场试验均证明了真空管井复合降水技术用于解决弱透水层和界面残留水疏干难题的有效性;并且对不同地层中真空度、孔隙水压力等变化规律进行了研究,发现地层中真空度均有一定的影响范围,且真空度在水平方向上随距主井距离的增加而逐渐降低;在垂直方向上真空度随深度总的规律是先增加后降低,并随土层性质及深度的不同而变化;土层内孔隙水压力也呈现出与真空度类似的变化规律。
基于室内物理模拟试验和现场试验测试结果对真空管井复合降水引起的真空场、渗流场的分布特征进行了总结分析,真空场的有效影响半径与真空管井自身真空度大小、地层特性、地层埋置深度等有关。真空管井自身真空度越大,真空场的有效影响半径越大。同等条件下,同一土层埋置越深,真空场的有效影响半径越大;并在安北区间试验数据的基础上,采用数值分析进行了验证,得到了与现场测试结果相近的变化规律。
在理论研究基础上,对井深、真空影响半径、抽水影响半径、单井出水量等关键设计参数进行分析,给出了相应计算方法和经验公式,为该技术的推广应用提供技术支持;根据现场试验情况,提出了真空管井的主要结构参数及密封措施;研制了环保型密封材料及真空管井复合降水自动控制系统。
With rapid development of city construction, subway traffic was also growing rapidly. It is difficult to handle underground water in the process of subway construction. There is a difficult problem in the process of Beijing subway construction as to dewatering perched water, aquitard, water in saturated soil and relict water in aquifer interface by using conventional precipitation method, and the construction has to be worked with water, which bring a hidden trouble to the tunnel excavation with the rapid economic way and a safe and civilized construction, it is a problem to be solved urgently in the subway construction. The new method of compound dewatering technique of vacuum tube well, the integration of vacuum technology and tube-well technology, is proposed in this thesis for solving the precipitation problem during construction. Indoor physical simulation test, field engineering test, field experimental study, the study of basic theory and engineering design have been conducted. The research results are of great significance in theory and engineering applications. The research work done is presented as follows:
Compound dewatering technique of vacuum tube well is an effective technology for solving the dewatering problems of aquitard and interface relict water according to physical simulation test and field test. The variation laws, such as degree of vacuum, pore water pressure in different strata, have been studied. The results show that there is a certain scope of influence of vacuum in strata, and the vacuum degree in the horizontal direction decreases gradually with the increase of the distance from the main well; the change law of degree of vacuum in the vertical direction increases firstly and then decreases with the depth of soil strata, and changes with different soil nature and depth; changes of pore water pressure in soil strata has also shown a similar law of degree of vacuum.
Based on the results of laboratory physical simulation test and field test, distribution characteristics of seepage field and vacuum field caused by compound dewatering technique of vacuum tube well have been analyzed, the effective influence radius of vacuum field are related to the degree of the vacuum in well, characteristics and buried depth of strata and so on. The greater the degree of the vacuum in well cause, the greater the effective influence radius of vacuum field are. Under the same conditions, the more deep the same stratum buried, the greater the effective influence radius of vacuum field are. Numerical analysis has been conducted to verify the test data gained in inter-zone of An Ding road and Bei Tucheng, and the variation similar to field measurement is presented.
Key design parameters, such as well depth, influence radius of vacuum, influence radius of pumping and single-well outflow have been analyzed on the theoretical research, the corresponding calculation method and empirical formula are given, which provide technical support for the extension and application of compound dewatering technique of vacuum tube well technology to provide technical support; the main structural parameters and sealing measures of vacuum tube well are raised according to field tests. Environmentally friendly material and automatic control system are developed.
通过室内物理模拟试验和现场试验均证明了真空管井复合降水技术用于解决弱透水层和界面残留水疏干难题的有效性;并且对不同地层中真空度、孔隙水压力等变化规律进行了研究,发现地层中真空度均有一定的影响范围,且真空度在水平方向上随距主井距离的增加而逐渐降低;在垂直方向上真空度随深度总的规律是先增加后降低,并随土层性质及深度的不同而变化;土层内孔隙水压力也呈现出与真空度类似的变化规律。
基于室内物理模拟试验和现场试验测试结果对真空管井复合降水引起的真空场、渗流场的分布特征进行了总结分析,真空场的有效影响半径与真空管井自身真空度大小、地层特性、地层埋置深度等有关。真空管井自身真空度越大,真空场的有效影响半径越大。同等条件下,同一土层埋置越深,真空场的有效影响半径越大;并在安北区间试验数据的基础上,采用数值分析进行了验证,得到了与现场测试结果相近的变化规律。
在理论研究基础上,对井深、真空影响半径、抽水影响半径、单井出水量等关键设计参数进行分析,给出了相应计算方法和经验公式,为该技术的推广应用提供技术支持;根据现场试验情况,提出了真空管井的主要结构参数及密封措施;研制了环保型密封材料及真空管井复合降水自动控制系统。
With rapid development of city construction, subway traffic was also growing rapidly. It is difficult to handle underground water in the process of subway construction. There is a difficult problem in the process of Beijing subway construction as to dewatering perched water, aquitard, water in saturated soil and relict water in aquifer interface by using conventional precipitation method, and the construction has to be worked with water, which bring a hidden trouble to the tunnel excavation with the rapid economic way and a safe and civilized construction, it is a problem to be solved urgently in the subway construction. The new method of compound dewatering technique of vacuum tube well, the integration of vacuum technology and tube-well technology, is proposed in this thesis for solving the precipitation problem during construction. Indoor physical simulation test, field engineering test, field experimental study, the study of basic theory and engineering design have been conducted. The research results are of great significance in theory and engineering applications. The research work done is presented as follows:
Compound dewatering technique of vacuum tube well is an effective technology for solving the dewatering problems of aquitard and interface relict water according to physical simulation test and field test. The variation laws, such as degree of vacuum, pore water pressure in different strata, have been studied. The results show that there is a certain scope of influence of vacuum in strata, and the vacuum degree in the horizontal direction decreases gradually with the increase of the distance from the main well; the change law of degree of vacuum in the vertical direction increases firstly and then decreases with the depth of soil strata, and changes with different soil nature and depth; changes of pore water pressure in soil strata has also shown a similar law of degree of vacuum.
Based on the results of laboratory physical simulation test and field test, distribution characteristics of seepage field and vacuum field caused by compound dewatering technique of vacuum tube well have been analyzed, the effective influence radius of vacuum field are related to the degree of the vacuum in well, characteristics and buried depth of strata and so on. The greater the degree of the vacuum in well cause, the greater the effective influence radius of vacuum field are. Under the same conditions, the more deep the same stratum buried, the greater the effective influence radius of vacuum field are. Numerical analysis has been conducted to verify the test data gained in inter-zone of An Ding road and Bei Tucheng, and the variation similar to field measurement is presented.
Key design parameters, such as well depth, influence radius of vacuum, influence radius of pumping and single-well outflow have been analyzed on the theoretical research, the corresponding calculation method and empirical formula are given, which provide technical support for the extension and application of compound dewatering technique of vacuum tube well technology to provide technical support; the main structural parameters and sealing measures of vacuum tube well are raised according to field tests. Environmentally friendly material and automatic control system are developed.
引文
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[2]叶锋,刘永亮等.城市复杂地区辐射井降水技术研究报告. 2004
[3]郑启宇,侯景岩,郭建国.论北京地铁”复-八”线施工降水方法的适用条件.建设中的北京地铁-地铁“复-八”线.中国铁道出版社,1999, 219-227
[4]侯景岩,郝静野,张富祥.越流补给井在地铁施工降水中的应用.建设中的北京地铁-地铁“复-八”线.中国铁道出版社. 1999, 228-230
[5]贺长俊,于福山,李铎.北京地铁施工中地下水的治理.建设中的北京地铁-地铁“复-八”线.中国铁道出版社,1999, 231-333
[6]侯景岩,陈元绍.“复-八”线地铁工程施工降水的实践与认识.建设中的北京地铁-地铁“复-八”线.中国铁道出版社. 1999, 299-314
[7]侯景岩,魏连伟.用降水回灌法改善北京地铁“复-八”线工程地质环境和施工条件.水文地质工程地质. 1997,(03):38-41
[8]宋龙喜,叶锋,周训.北京地铁施工中若干地下水处理方法.工程勘察,2006,(05):19-22
[9]付兆明,伍锦湛等.轻型井点降水在某基坑组合支护中的应用.广东土木与建筑, 2003,(09):6-8
[10]卜万连.轻型井点降水工程常见的问题及预防措施.平原大学学报, 2000,(04):50.
[11]辛明政,林国海,徐永泉.逆作法施工中利用喷射井点降水法.低温建筑技术, 1996,(02): 14-16
[12]卜长根,孙孝庆,刘国平.同心式射流泵在深层井点降水中的应用.水文地质工程地质, 2002,(01):54-55,69
[13]刘瑛文,李梅远,胡青松.浅谈喷射井点法在软基开挖时的应用.黑龙江水专学报, 2003,(03):82-83
[14]王美华,季方.上海铁路南站地下工程关键施工技术.上海建设科技, 2005, (03):5-8
[15]刘少福,罗建华.上海外滩金融中心深基坑施工技术.施工技术, 2000,(01):12-13,25.
[16]张振华.正大广场基坑降水技术.上海地质, 1999,(02):34-37
[17]欧阳效勇,李海等.润扬大桥悬索桥南锚锭深基坑降水设计与施工.桥梁建设,2004,4:50 -53
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