【正文】 ter seepage through the pores, cracks and fissures of the foundation materials, and water seepage through dam body and then to the bottom through the joints between the body of the dam and its foundation at the base exert an uplift pressure on the base of the dam. According to the [6], the uplift pressure intensities at the heel and toe of the dam should be taken equal to their respective hydrostatic pressures and joined the intensity ordinates by a straight line. When 221 Hp w??drainage galleries are provided to relieve the uplift, the remended uplift at the face of the gallery is equal to the hydrostatic pressure at toe plus 1/3rd of the difference between the hydrostatic pressures at the heel and the toe, respectively. . Earthquake Forces An earthquake produces waves, which are capable of shaking the earth upon which the gravity dams rest, in every possible direction. The effect of an earthquake is, therefore, equivalent to imparting acceleration to the foundations of the dams in the direction in which the wave is traveling at the moment. Generally, an earthquake induces horizontal acceleration (h) and vertical acc eleration (v). The values of these accelerations are generally expressed as per centage of the acceleration due to generally sufficient for high dams in seismic zones. In extremely seismic regions and in conservative Designs even a value up to g may sometimes be adopted [7]. Earthquake loadings should be checked for horizontal as well as vertical earth quake accelerations. While earthquake acceleration might take place in any direc tion,the analysis should be performed for the most unfavorable direction. The earthquake loadings used in the design of concrete gravity dams are based on design earthquakes and sitespecific motions determined from seismological eva luation. At a minimum, a seismological evaluation should be performed on all pro jects located in seismic zones 1, 2, and 3 of Bangladesh [8], depending upon the severity of earthquakes. The seismic coefficient method of analysis should be used in determining the resultant location and sliding stability of dams. In strong seismicity areas, a dynamic seismic analysis is required for the internal stress analysis. . Effect of Vertical Acceleration (ɑv) A vertical acceleration may either act downward or upward. When it acts in the upward direction, then the foundation of the dam will be lifted upward and bees closer to the body of the dam, and thus the effective weight of the dam will increase and hence, the stress developed will increase. When the vertical acceleration acts downward, the foundation shall try to move downward away from the dam body。 7) Earth quake forces。這兩種一般混 凝土施工方法在混凝土重力壩是為常規(guī)放置大體積混凝土和碾壓混凝土。上下游的水壓力 。 揚壓力 水通過空隙滲流，基礎(chǔ)材料的裂紋和裂縫，壩體滲水，然后通過壩體和壩基之間對大壩產(chǎn)生壓力，根據(jù) 6，壩體和壩基之間的壓力強度應(yīng)該等于各自的靜水 壓力和直線連接的強度坐標，為了緩解排水廊道上升，廊道表面的靜水壓力應(yīng)等于根部和頂部靜水壓力的 1/3。這樣就減輕了大壩的實際重量和破壞大壩的穩(wěn)定性。）這個力也會產(chǎn)生最糟糕的結(jié)果。當垂直加速度向上時，大壩的壩基就會被抬上來，靠近大壩的壩體，這樣大壩的實際重量就會增加，因此，形成的壓力也會增加。水平水壓力通過存儲在大壩的上游側(cè)和下游側(cè)水的重量來施加。 2 負載 在混凝土重力壩的設(shè)計中，準確計算出荷載的穩(wěn)定性和壓力力分析是非常重要的。這種類型的結(jié)構(gòu)是非常耐用的，并且只需要很少的維護。 5) Earth and silt pressures。 kh = fraction of gravity adopted for h