【正文】 ning many variables ha made practicable the method of Finite Element Analysis. In this method, a plicated structure is divided into a number of separate equilibrium conditions, and strains are rendered patible, thus leading to a plete analysis of stress and strain distribution throughout the structure. Problems of materials. Each of the two basic dam materials, concrete and earth or rock fill, has a weakness that must be overe by the proper design of the dam. Weaknesses of concrete.. Concrete is weak in tensile strength。 大壩設(shè)計(jì)的基本問(wèn)題被分為兩個(gè)基本類型： M 壩 和 E 壩 ， M 壩是用來(lái)在峽谷的峽谷中橫跨河流，如在群山中這類壩可能非常高，但所需的 總體材料受到限制。 混凝土的弱點(diǎn)，混凝土的弱點(diǎn)在于抗拉強(qiáng)度，因?yàn)樗苋菀妆焕?，混凝土大壩因此要被設(shè)計(jì)承受最小拉應(yīng)力和利用混凝土大的壓應(yīng)力或盡可能地承受垂直荷載。 6 土由固體物質(zhì)，水和空氣構(gòu)成，土受荷而壓縮，如出現(xiàn)在大壩建筑，排出水和空氣導(dǎo)致增加固體物質(zhì)間的壓力，當(dāng)有很高的滲透比時(shí)，土趨向于產(chǎn)生不同的壓力和達(dá)到臨界狀態(tài)，這時(shí)它的狀態(tài)如同液體。假如能得到足夠的土用 于壩址的合攏在光山區(qū)域，它可能比堤壩更需要采石場(chǎng)的巖石和構(gòu)造巖石。用這種方法，一個(gè)復(fù)雜結(jié)構(gòu)被分為許多單獨(dú)的平衡條件，而且所有拉力都具有兼容性，這樣可以對(duì)整個(gè)結(jié)構(gòu)的壓力的分布全面地來(lái)分析。混泥土大壩的整體形式在側(cè)面上分為很多種類。 and means for permitting ships or fish to pass the dam. A dam therefore is the central structure in a multipurpose scheme aiming at the conservation of water resources. The multipurpose dam holds special importance in the underdeveloped counties, where a small nation may reap enormous benefits in agriculture and industry from a single dam. Dams fall into several distinct classes, by profile and by building material. The decision as to which type of dam be build depends largely on the foundation conditions in the valley and the construction materials available. Basically, the choice of materials now lies between concrete, soils, and rockfill. Though a number of dams were built in the past of jointed masonry, this practice is now largely obsolete, The monolithic form of concrete dams permits greater variations in profile, according to the extent water pressure is resisted by the deadweight of the structure, is transferred laterally to buttresses, or is carried by horizontal arching across the valley to abutments formed by the sides of the valley. Basic Problems in Dam Design Most modern dams continue to be of two basic types: masonry (concrete) and embankment (earthfill). Masonry dams are typically used to block streams running through narrow go