百米级沥青混凝土心墙坝渗流特性及坝坡稳定性研究
发布时间：2018-10-09 20:37
【摘要】：沥青混凝土心墙坝是一种新兴的坝体结构,在过去的50年中得到了大力发展。随着筑坝技术的进一步发展与成熟,筑坝高度也随之增加,心墙局部开裂事件时有发生,但现阶段对沥青混凝土心墙局部开裂时坝体渗透稳定性以及坝坡稳定性的研究较少。针对心墙裂缝问题,本文首先研究了沥青混凝土心墙坝心墙局部开裂时的渗透稳定性,并分析了心墙开裂时库水位的升降对上、下游坝坡稳定性的影响,最后对某水电站沥青混凝土心墙坝工程进行了渗流研究,主要开展的研究内容及得出的相应成果如下:首先研究了心墙裂缝开裂位置、裂缝缝长、缝宽、不同水头高度以及过渡料和堆石体渗透系数的变化对总体渗流量的影响,发现:裂缝缝宽对渗流场的影响最小,其次为裂缝相对位置,对渗流场影响最大的为裂缝缝长;相比堆石体材料,过渡料材料渗透系数主要影响裂缝处的渗流量;裂缝开裂时,裂缝处附近的过渡料材料均超过了过渡料最大允许坡降,造成了渗透破坏;裂缝过长会导致渗流出口处的水力坡降大于排水棱体的允许坡降,造成渗透破坏。其次,研究了心墙局部开裂且库水位变化对沥青混凝土心墙坝坝坡稳定性的影响,发现:影响坝坡稳定性的最敏感位置位于靠近坝基的位置;随着裂缝开裂长度的增长,下游坝坡稳定性降低,且降幅明显,处于危险状态;当库水位变化时,过渡料渗透系数对上游坝坡稳定性的影响较小,下游坝坡稳定性的影响较大,而上游坝坡稳定性受堆石体渗透系数的影响巨大,对下游坝坡稳定性的影响较小;库水位变化幅度的不同主要影响上游坝坡稳定性的变化幅度,对下游坝坡稳定性的影响较小;库水位变化速度的快慢主要影响上游坝坡稳定性的变化速度与幅度,库水位降低速度越快,上游坝坡稳定性降低越迅速和明显。最后,研究了某水电站不同运行工况下库区整体三维渗流及方案优化研究,发现:大坝在不同运行状态下均具有良好的防渗能力,且满足大坝的渗透稳定性要求;该沥青混凝土心墙坝的渗流以绕渗为主,帷幕灌浆对坝底渗流量影响较大,在工程中应对沙卵砾石覆盖层及部分强风化层进行换填;心墙局部开裂对整个大坝的渗流量影响巨大,较小的裂缝即可对整个大坝的总体渗流量造成成倍的增长,在实际工程中应防止心墙局部开裂的情况发生,并应该严格杜绝缝长过长的现象发生,保证沥青混凝土心墙坝的整体防渗性能及大坝的渗透稳定性。
[Abstract]:Bituminous concrete core dam is a new type of dam structure, which has been developed greatly in the past 50 years. With the further development and maturity of dam construction technology, the height of dam construction also increases, and the local cracking of core wall occurs from time to time. However, there is little research on the seepage stability of dam body and the stability of dam slope during local cracking of asphalt concrete core wall at present. Aiming at the crack problem of core wall, this paper first studies the seepage stability of the core wall of asphalt concrete core dam, and analyzes the influence of the rise and fall of reservoir water level on the stability of upstream and downstream dam slope when the core wall cracks. Finally, the seepage research of asphalt concrete core dam of a hydropower station is carried out. The main research contents and corresponding results are as follows: firstly, the crack location, crack length, crack width, crack length, crack width of core wall are studied. It is found that the influence of fracture width on the seepage field is the least, followed by the relative position of the fracture, and the fracture length is the biggest influence on the seepage field by the change of the water head height and the permeability coefficient of the transition material and the rockfill. Compared with the rockfill material, the permeability coefficient of the transition material mainly affects the seepage flow at the crack, and when the crack cracks, the transition material near the crack exceeds the maximum allowable slope gradient of the transition material, which results in the seepage damage. If the cracks are too long, the hydraulic slope at the seepage outlet will be larger than the allowable slope of the drainage edge, resulting in seepage damage. Secondly, the influence of the local cracking of core wall and the change of reservoir water level on the stability of asphalt concrete core wall dam slope is studied. It is found that the most sensitive position affecting the stability of the dam slope lies near the dam foundation, and with the increase of crack length, The stability of the downstream dam slope is decreased, and the decrease is obvious, which is in a dangerous state. When the water level of the reservoir changes, the influence of the permeability coefficient of the transition material on the stability of the upstream dam slope is small, and the influence of the downstream dam slope stability is greater. However, the stability of upstream dam slope is greatly affected by the rockfill permeability coefficient, and the influence on the stability of downstream dam slope is small, while the variation of reservoir water level mainly affects the change range of upstream dam slope stability, while the influence of downstream dam slope stability is small. The speed of water level change mainly affects the change speed and amplitude of upstream dam slope stability. The faster the reservoir water level decreases, the faster and more obvious the upstream dam slope stability will be. Finally, the whole three-dimensional seepage flow and optimization of the reservoir area under different operating conditions of a hydropower station are studied. It is found that the dam has a good anti-seepage capability under different operation conditions, and meets the requirements of seepage stability of the dam; The percolation of the asphalt concrete core dam is mainly around seepage, and curtain grouting has a great influence on the seepage flow at the bottom of the dam. The sand gravel overburden and some strong weathering layers should be replaced in the project. The local crack of the core wall has a great influence on the seepage flow of the whole dam, and the small crack can cause the increase of the total seepage flow of the whole dam, and the local crack of the core wall should be prevented from happening in the actual engineering. The phenomenon of long joint length should be strictly eliminated to ensure the overall impervious performance of the asphalt concrete core dam and the seepage stability of the dam.
【学位授予单位】：西安理工大学
【学位级别】：硕士
【学位授予年份】：2017
【分类号】：TV642;TV223
[Abstract]:Bituminous concrete core dam is a new type of dam structure, which has been developed greatly in the past 50 years. With the further development and maturity of dam construction technology, the height of dam construction also increases, and the local cracking of core wall occurs from time to time. However, there is little research on the seepage stability of dam body and the stability of dam slope during local cracking of asphalt concrete core wall at present. Aiming at the crack problem of core wall, this paper first studies the seepage stability of the core wall of asphalt concrete core dam, and analyzes the influence of the rise and fall of reservoir water level on the stability of upstream and downstream dam slope when the core wall cracks. Finally, the seepage research of asphalt concrete core dam of a hydropower station is carried out. The main research contents and corresponding results are as follows: firstly, the crack location, crack length, crack width, crack length, crack width of core wall are studied. It is found that the influence of fracture width on the seepage field is the least, followed by the relative position of the fracture, and the fracture length is the biggest influence on the seepage field by the change of the water head height and the permeability coefficient of the transition material and the rockfill. Compared with the rockfill material, the permeability coefficient of the transition material mainly affects the seepage flow at the crack, and when the crack cracks, the transition material near the crack exceeds the maximum allowable slope gradient of the transition material, which results in the seepage damage. If the cracks are too long, the hydraulic slope at the seepage outlet will be larger than the allowable slope of the drainage edge, resulting in seepage damage. Secondly, the influence of the local cracking of core wall and the change of reservoir water level on the stability of asphalt concrete core wall dam slope is studied. It is found that the most sensitive position affecting the stability of the dam slope lies near the dam foundation, and with the increase of crack length, The stability of the downstream dam slope is decreased, and the decrease is obvious, which is in a dangerous state. When the water level of the reservoir changes, the influence of the permeability coefficient of the transition material on the stability of the upstream dam slope is small, and the influence of the downstream dam slope stability is greater. However, the stability of upstream dam slope is greatly affected by the rockfill permeability coefficient, and the influence on the stability of downstream dam slope is small, while the variation of reservoir water level mainly affects the change range of upstream dam slope stability, while the influence of downstream dam slope stability is small. The speed of water level change mainly affects the change speed and amplitude of upstream dam slope stability. The faster the reservoir water level decreases, the faster and more obvious the upstream dam slope stability will be. Finally, the whole three-dimensional seepage flow and optimization of the reservoir area under different operating conditions of a hydropower station are studied. It is found that the dam has a good anti-seepage capability under different operation conditions, and meets the requirements of seepage stability of the dam; The percolation of the asphalt concrete core dam is mainly around seepage, and curtain grouting has a great influence on the seepage flow at the bottom of the dam. The sand gravel overburden and some strong weathering layers should be replaced in the project. The local crack of the core wall has a great influence on the seepage flow of the whole dam, and the small crack can cause the increase of the total seepage flow of the whole dam, and the local crack of the core wall should be prevented from happening in the actual engineering. The phenomenon of long joint length should be strictly eliminated to ensure the overall impervious performance of the asphalt concrete core dam and the seepage stability of the dam.
【学位授予单位】：西安理工大学
【学位级别】：硕士
【学位授予年份】：2017
【分类号】：TV642;TV223
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相关期刊论文 前10条
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