【導讀】全球城市化進程的加快將會對人類將來的生存方式產(chǎn)生重大影響。礦物資源來維持此增長趨勢。解決這一難題的辦法有三大渠道復合而成：農(nóng)業(yè)用。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。的利用，作為本章要描述的內(nèi)容，將提供針對這些趨勢的解決辦法。類似的，在陡峭的山坡上使用階地掩土住宅會有助于。在多山地區(qū)保護寶貴的可耕平地。的居住舒適度，改善生活質(zhì)量。開采已達到更深的地層以下，觸及更難以讓人接受或是更敏感的區(qū)域。有這些發(fā)展均涉及地下工程。部分人口居住在少于20%的國土上。地減少，向城市人口運送食物和原材料的問題日益增長。而且日本法律規(guī)定必須建造靠近陽光的堅固的維護設(shè)施。食生產(chǎn)能力，日本政府保護農(nóng)業(yè)用地。網(wǎng)絡(luò)司空見慣歸咎于缺乏協(xié)調(diào)以及使用設(shè)施的歷史性變革以及交通系統(tǒng)的發(fā)展。于日本地下工業(yè)情況的論壇。使用設(shè)施到展望中的用于災(zāi)難時刻保護通訊網(wǎng)絡(luò)的地下走廊。

　　

【正文】 s solely by vertical members in bending is usually less economical , since achieving sufficient bending resistance in the columns and connecting girders will require more material and construction energy than using walls or diagonal members . 6. Sufficient horizontal diaphragm action should be provided floor . This will help to bring the various resisting elements to work together instead of separately . 7. Create megaframes by joining large vertical and horizontal ponents such as two or more elevator shafts at multistory intervals with a heavy floor subsystems , or by use of very deep girder trusses . Remember that all highrise buildings are essentially vertical cantilevers which are supported at the ground . When the above principles are judiciously applied , structurally desirable schemes can be obtained by walls , cores , rigid frames, tubular construction , and other vertical subsystems to achieve horizontal strength and rigidity . Some of these applications will now be described in subsequent sections in the following . ShearWall Systems When shear walls are patible with other functional requirements , they can be economically utilized to resist lateral forces in highrise buildings . For example , apartment buildings naturally require many separation walls . When some of these are designed to be solid , they can act as shear walls to resist lateral forces and to carry the vertical load as well . For buildings up to some 20storise , the use of shear walls is mon . If given sufficient length ,such walls can economically resist lateral forces up to 30 to 40 stories or more . However , shear walls can resist lateral load only the plane of the walls ( in a diretion perpendicular to them ) . There fore ,it is always necessary to provide shear walls in two perpendicular directions can be at least in sufficient orientation so that lateral force in any direction can be resisted . In addition , that wall layout should reflect consideration of any torsional effect . In design progress , two or more shear walls can be connected to from Lshaped or channelshaped subsystems . Indeed , internal shear walls can be connected to from a rectangular shaft that will resist lateral forces very efficiently . If all external shear walls are continuously connected , then the whole buildings acts as tube , and connected , then the whole buildings acts as a tube , and is excellent ShearWall Seystems resisting lateral loads and torsion . Whereas concrete shear walls are generally of solid type with openings when necessary , steel shear walls are usually made of trusses . These trusses can have single diagonals , “X”diagonals , or“K”arrangements . A trussed wall will have its members act essentially in direct tension or pression under the action of view , and they offer some opportunity and deflectionlimitation point of view , and they offer some opportunity for peration between members . Of course , the inclined members of trusses must be suitable placed so as not to interfere with requirements for wiondows and for circulation service perations though these walls . As stated above , the walls of elevator , staircase ,and utility shafts form natural tubes and are monly employed to resist both vertical and lateral forces . Since these shafts are normally rectangular or circular in crosssection , they can offer an efficient means for resisting moments and shear in all directions due to tube structural action . But a problem in the design of these shafts is provided sufficient strength around door openings and other perations through these elements . For reinforced concrete construction , special steel reinforcements are placed around such opening .In steel construction , heavier and more rigid connections are required to resist racking at the openings . In many highrise buildings , a bination of walls and shafts can offer excellent resistance to lateral forces when they are suitably located ant connected to one another . It is also desirable that the stiffness offered these subsystems be moreorless symmertrical in all directions . RigidFrame Systems In the design of architectural buildings , rigidframe systems for resisting vertical and lateral loads have long been accepted as an important and standard means for designing building . They are employed for lowand medium means for designing buildings . They are employed for low and medium up to highrise building perhaps 70 or 100 stories high . When pared to shearwall systems , these rigid frames both within and at the outside of a buildings . They also make use of the stiffness in beams and columns that are required for the buildings in any case , but the columns are made stronger when rigidly connected to resist the lateral as well as vertical forces though frame bending . Frequently , rigid frames will not be as stiff as shearwall construction , and therefore may produce excessive deflections for the more slender highrise buildings designs . But because of this flexibility , they are often considered as being more ductile and thus less susceptible to catastrophic earthquake failure when pared with ( some ) shearwall designs . For example , if over stressing occurs at certain portions of a steel rigid frame ( .,near the joint ) , ductility will allow the structure as a whole to deflect a little more , but it will by no means collapse even under a much larger force than expected on the structure . For this reason , rigidframe construction is considered by some to be a “best”seismicresisting type for highrise steel buildings . On the other hand ,it is also unlikely that a welldesigned sharewall system would collapse. In the case of concrete rigid frames ,there is a divergence of opinion . It true that if a concrete rigid frame is designed in t