Crane Valley Dam is located on the North Fork of Willow Creek, a tributary of the San Joaquin River, in Madera County, California. The dam and reservoir are owned and operated by Pacific Gas and Electric Company (PG&E) of San Francisco, California. Built between 1901 and 1911, the dam is composed of a 145-foot high, earth and rockfill embankment, with a thin, central concrete core wall. The dam is 1,880 feet long and has a minimum crest elevation of approximately 3380 feet (NGVD). The dam varies in cross-section, and includes full hydraulic fill sections (i.e., hydraulic fill embankments on both sides of the core wall) near the west and east ends of the dam. In the mid-section of the dam, where the maximum height occurs, the embankment on the upstream side of the core wall was constructed of hydraulic fill and the embankment on the downstream side of the core wall was constructed of dumped rockfill. The rockfill was progressively thickened in a downstream direction over a period of 15 years (between 1914 and 1929), generally by side-dumping quarry run rockfill from the downstream edge of the crest. An aerial view of the dam in presented in Figure 1. Because of changes in the state-of-practice in seismic stability analyses since the dam was last evaluated in the mid 1970s, and because of the increase in seismic hazard in the dam vicinity, PG&E initiated a re-evaluation of the seismic stability of the dam. The dam was re-evaluated for earthquake ground shaking caused by a local (random) earthquake with moment magnitude, Mw, of 6V4, and a magnitude 8.0 earthquake on the distant San Andreas fault. Results of these analyses showed that the dam's hydraulic fill embankments would experience large deformations during and after the earthquake shaking postulated for the site. The magnitude of the deformations was found to be excessive and would likely cause an uncontrolled release of the reservoir water at the current normal maximum operating level. Accordingly, it was concluded that measures are needed to improve the seismic stability and performance of the dam. This paper describes the ground motion studies, field investigations, engineering analyses, and the conceptual design of seismic retrofits to improve the seismic performance of the dam. The field investigations included onshore and offshore in situ testing and geophysical measurements. The engineering analyses included static, seepage, and dynamic finite element analyses to evaluate the potential for liquefaction of the hydraulic fill embankment and its post-earthquake stability. Non-linear finite difference (FLAC) analyses were also performed to estimate the permanent deformation of the liquefied upstream hydraulic fill slopes, to aid in the design of retrofit of the concrete core wall.
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机译：Crane Valley Dam位于加利福尼亚Madera County的圣Joaquin River河的北叉北叉子。大坝和水库由加利福尼亚州旧金山的太平洋天然气和电气公司（PG＆E）拥有和运营。建于1901年至1911年，大坝由145英尺高，地球和堆石路堤组成，具有薄，中央混凝土芯墙。大坝长1,880英尺长，最小嵴高度约为3380英尺（NGVD）。该坝在横截面中变化，并包括靠近大坝的西和东端附近的完整液压填充部分（即芯墙两侧的液压填充路堤）。在大坝的中间部分，在最大高度发生的情况下，芯壁上游侧的堤防由液压填充和芯壁下游侧的堤防构成，由倾倒的堆石构成。在下游方向上（1914年至1929年）（在1914和1929年间），岩石逐渐增厚，通常通过倾倒采石场从冠的下游边缘倾斜。在图1中呈现的大坝的鸟瞰图。由于在20世纪70年代中期，水坝终于评估了地震稳定性分析中的实践状态的变化，并且由于大坝附近的地震危害增加， PG＆E启动了对大坝的地震稳定性的重新评估。通过局部幅度，MW，6V4的瞬间（随机）地震，重新评估大坝的地震地面震动，以及遥远的SANDREAS故障的8.0级地震。这些分析的结果表明，大坝的液压填充路堤在地震震动期间和之后的液压填充路堤将体现大变形。发现变形的幅度过度，并且可能导致储层在当前正常的最大操作水平下不受控制的释放。因此，得出结论，需要采取措施来提高水坝的地震稳定性和性能。本文介绍了地面运动研究，现场调查，工程分析以及地震改造的概念设计，以提高大坝的地震性能。现场调查包括陆上和海上原位测试和地球物理测量。工程分析包括静态，渗流和动态有限元分析，以评估液压填充路堤的液化潜力及其地震后稳定性。还进行了非线性有限差异（FLAC）分析，以估计液化上游液压填充坡的永久变形，以帮助设计混凝土芯壁的改造。
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