【摘要】：瀝青混凝土心墻壩是一種新興的壩體結(jié)構(gòu),在過去的50年中得到了大力發(fā)展。隨著筑壩技術(shù)的進(jìn)一步發(fā)展與成熟,筑壩高度也隨之增加,心墻局部開裂事件時(shí)有發(fā)生,但現(xiàn)階段對(duì)瀝青混凝土心墻局部開裂時(shí)壩體滲透穩(wěn)定性以及壩坡穩(wěn)定性的研究較少。針對(duì)心墻裂縫問題,本文首先研究了瀝青混凝土心墻壩心墻局部開裂時(shí)的滲透穩(wěn)定性,并分析了心墻開裂時(shí)庫水位的升降對(duì)上、下游壩坡穩(wěn)定性的影響,最后對(duì)某水電站瀝青混凝土心墻壩工程進(jìn)行了滲流研究,主要開展的研究?jī)?nèi)容及得出的相應(yīng)成果如下:首先研究了心墻裂縫開裂位置、裂縫縫長(zhǎng)、縫寬、不同水頭高度以及過渡料和堆石體滲透系數(shù)的變化對(duì)總體滲流量的影響,發(fā)現(xiàn):裂縫縫寬對(duì)滲流場(chǎng)的影響最小,其次為裂縫相對(duì)位置,對(duì)滲流場(chǎng)影響最大的為裂縫縫長(zhǎng);相比堆石體材料,過渡料材料滲透系數(shù)主要影響裂縫處的滲流量;裂縫開裂時(shí),裂縫處附近的過渡料材料均超過了過渡料最大允許坡降,造成了滲透破壞;裂縫過長(zhǎng)會(huì)導(dǎo)致滲流出口處的水力坡降大于排水棱體的允許坡降,造成滲透破壞。其次,研究了心墻局部開裂且?guī)焖蛔兓瘜?duì)瀝青混凝土心墻壩壩坡穩(wěn)定性的影響,發(fā)現(xiàn):影響壩坡穩(wěn)定性的最敏感位置位于靠近壩基的位置;隨著裂縫開裂長(zhǎng)度的增長(zhǎng),下游壩坡穩(wěn)定性降低,且降幅明顯,處于危險(xiǎn)狀態(tài);當(dāng)庫水位變化時(shí),過渡料滲透系數(shù)對(duì)上游壩坡穩(wěn)定性的影響較小,下游壩坡穩(wěn)定性的影響較大,而上游壩坡穩(wěn)定性受堆石體滲透系數(shù)的影響巨大,對(duì)下游壩坡穩(wěn)定性的影響較小;庫水位變化幅度的不同主要影響上游壩坡穩(wěn)定性的變化幅度,對(duì)下游壩坡穩(wěn)定性的影響較小;庫水位變化速度的快慢主要影響上游壩坡穩(wěn)定性的變化速度與幅度,庫水位降低速度越快,上游壩坡穩(wěn)定性降低越迅速和明顯。最后,研究了某水電站不同運(yùn)行工況下庫區(qū)整體三維滲流及方案優(yōu)化研究,發(fā)現(xiàn):大壩在不同運(yùn)行狀態(tài)下均具有良好的防滲能力,且滿足大壩的滲透穩(wěn)定性要求;該瀝青混凝土心墻壩的滲流以繞滲為主,帷幕灌漿對(duì)壩底滲流量影響較大,在工程中應(yīng)對(duì)沙卵礫石覆蓋層及部分強(qiáng)風(fēng)化層進(jìn)行換填;心墻局部開裂對(duì)整個(gè)大壩的滲流量影響巨大,較小的裂縫即可對(duì)整個(gè)大壩的總體滲流量造成成倍的增長(zhǎng),在實(shí)際工程中應(yīng)防止心墻局部開裂的情況發(fā)生,并應(yīng)該嚴(yán)格杜絕縫長(zhǎng)過長(zhǎng)的現(xiàn)象發(fā)生,保證瀝青混凝土心墻壩的整體防滲性能及大壩的滲透穩(wěn)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.
【學(xué)位授予單位】：西安理工大學(xué)
【學(xué)位級(jí)別】：碩士
【學(xué)位授予年份】：2017
【分類號(hào)】：TV642;TV223

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本文編號(hào)：2260704