【正文】 用地壓力 將設(shè)施置于地下是緩解由于世界人口增長所帶來的城市化問題的一種有希望的辦法。解決這一難題的辦法有三大渠道復(fù)合而成：農(nóng)業(yè)用地的保護(hù)從而得到更深入的利用；日益增長的全球城市人口；對保護(hù)和改善環(huán)境日益增長的關(guān)注，特別是關(guān)于全球氣候變暖以及人口增長帶來的影響。這是那些可以提供糧食產(chǎn)品的肥沃土地。雖然沒有高額地價(jià)，但是建造地下設(shè)施的高額花費(fèi)將是地下空間利用的一大攔路虎。隨著填加更多的地鐵線，在更深土層中才會發(fā)現(xiàn)比較規(guī)整的區(qū)域。這類走廊對于在城市地鐵站和中心生產(chǎn)去附近以及市區(qū)外安置地點(diǎn)間運(yùn)送廢棄物和能源也十分有效。對于現(xiàn)代的鋼架系統(tǒng)支撐設(shè)計(jì)，如無特殊承載需要，無需加大柱和梁的尺寸，而通過增加板就可以實(shí)現(xiàn)。 3. 增加最有效的抗彎構(gòu)件的截面。 但是，剪力墻只能抵抗平行于墻平面的荷載（也就是說不能抵抗垂直于墻的荷載）。 對于很多高層建筑，如果墻體和筒架進(jìn)行合理地安排與連接，會起到很好的抵抗側(cè)向荷載的作用。新建筑規(guī)范對所謂延性混凝土框架有專門的規(guī)定。盡管這樣，混凝土框架設(shè)計(jì)還是具備既經(jīng)濟(jì)又實(shí)用的特性。 框架結(jié)構(gòu) 在建筑物結(jié)構(gòu)設(shè)計(jì)中，用于抵抗豎向和水平荷載的 框架結(jié)構(gòu)，常作為一個(gè)重要且標(biāo)準(zhǔn)的型式而被采用。并且，墻體設(shè)計(jì)還應(yīng)考慮扭轉(zhuǎn)的問題。 4. 通過設(shè)計(jì)使大部分豎向荷載，直接作用于主要的抗彎構(gòu)件。高層建筑中的柱、梁、墻及板等經(jīng) 常需要采用特殊的結(jié)構(gòu)布置和特殊的材料，以抵抗相當(dāng)高的側(cè)向荷載以及變形。這些概念都是針對城市建筑的升級，將 最終導(dǎo)致地表形成更開闊的空間以及更高效更吸引人的全局環(huán)境。一條從 Marunouchi 到Shinjuku 的高速干線已被設(shè)計(jì)到 50m 深。 地下空間規(guī)劃 對地下空間利用的有效規(guī)劃是發(fā)展地下設(shè)施的前奏。隨著人口和經(jīng)濟(jì)的增長，農(nóng)業(yè)用地減少，向城市人口運(yùn)送食物和原材料的問題日益增長。 通過將特殊器材設(shè)備置于地下，城市地表可被更有效地利用，這樣就可釋放出空間供農(nóng)業(yè)和娛樂使用 。這些趨勢同樣導(dǎo)致針對能源繁衍存貯系統(tǒng)以及用于處理危險(xiǎn)廢料（包括化學(xué)，生物以及放射性廢料）的國家設(shè)施設(shè)計(jì)的改善和提高，同樣也改善了國家高速運(yùn)輸體系。結(jié)果是市中心土地價(jià)格驚人昂貴（高達(dá) 50 萬美圓 /平米）并且很難為人們提供住房，交通，設(shè)施服務(wù)。 。地下設(shè)施以其自身特點(diǎn)成為一種典型的儲能設(shè)施。 高層建筑的豎向構(gòu)件從上到下逐層對累積的重力和荷載進(jìn)行傳遞，這就要有較大尺寸的墻體或者柱體來進(jìn)行承載。在地震荷載作用下，頂部質(zhì)量的增加將會使側(cè)向荷載劇增。 應(yīng)當(dāng)注意的是，所有高層建筑的本質(zhì)都是地面支撐的懸臂結(jié)構(gòu)。從強(qiáng)度和變形控制角度來說，桁架有著很好的功效，并且管道可以在構(gòu)件之間穿過。因此，框架結(jié)構(gòu)常被視為最好的高層抗震結(jié)構(gòu)。 and growing concern for the maintenance and improvement of the environment, especially regarding global warming and the impact of population growth. Underground space utilization, as this chapter describes, offers opportunities for helping address these trends. By moving certain facilities and function underground, surface land in urban areas can be used more effectively , thus freeing space for agricultural and recreational purpose. Similarly, the use of terraced earth sheltered housing. Using underground space also enables humans to live more fortably in densely populated areas while improving the quality of live. On an urban or local level, the use of underground facilities is rising to acmodate the plex demands of today`s society while improving the environment . For example, both urban and rural areas are requiring improved transportation, utility, and recreational services. The state of traffic congestion in many urban areas of the world is at a critical level for the support of basic human living, and it is difficult if not impossible to add new infrastructure at ground level without causing an unacceptable deterioration of the surface environment or an unacceptable relocation of existing land uses and neighborhoods. On a national level in countries around the world, global trends are causing the creation and extension of mining developments and oil or gas recovery at greater depths and in more inaccessible or sensitive locations. Three trends have also led to the developments of improved designs for energy generation and storage systems as well as national facilities for dealing with hazardous waste (including chemical, biological, and radioactive waste ), and improved highspeed national transportation systems .All these developments involve use of the underground . Land Use Pressures Placing facilities underground is a promising method for helping ease land use pressures caused by the growth and urbanization of the world`s population. Although the average population density in the world is not large, the distribution of population is very uneven. A map of population density in the world is not large ,areas of the world are essentially uninhabited . These areas are for the most part deserts ,mountainous regions, or regions of severe cold that do not easily support human habitation. If one examines China ,for example ,the average population density is approximately 100 persons per square kilometer, but the vat majority of the one billionplus population lives on less than 20 percent of the land area. this is the fertile land that can support food production. However, due to population growth, urbanization, and economic growth, this same land must now support extensive transportation systems, industrial and mercial development, and increasing demands for housing, As the population and economy grow, the land available for agriculture shrinks, and the problems of transporting food and raw materials to an urban population increase. By the year 2020 it is estimated that 70 percent of the world`s population will inhabit urban areas. The same trend are evident in Japan, where approximately 80 percent of the land area is mountainous,90 percent of the population lives on the coastal plains, and economic development is concentrated in relatively few economic development is concentrated in relatively few economic centers .The flatlying land is generally the most fertile and is historically the region of settlement . Other factors adding to population density include the traditional building style , which is lowrise , and Japanese law that contain strong provisions for maintenance of access to sunlight .Also ,to retain domestic food production capability , the Japanese government has protected agricultural land from development. The bination of these historical and political factors together with a strong migration of businesses and individuals to the economic centers has created enormous land use pressure. The result is an astronomically high cost of land in city centers (as high as US $500,00 per square meter) and difficulty in an providing housing, transportation, and utility services for the population. Typical business employees cannot afford to live near the city center where they work and may have to mute one to two hours each way from an affordable area. To service the expanding metropolitan area, public agencies must upgrade roads and build new transit lines and utilizes. Land costs for such work are so high that in central Tokyo, the cost of land may represent over 95 percent of the total cost of a project. The problem of land use pressures and related economi