【正文】 ncing the role of the wall cracking strength, superlong construction of pouring after sewing or mixed in concrete ways to UEA expansive agent is effective in reducing measures undertaken Crack. 60d of the late use of concrete strength, can reduce the amount of cement concrete。 (5) the quality control of raw materials, timely grasp the construction environment, in strict accordance with the construction norms of construction。 13 (6) the use of thinlayer approach for irrigation, to ensure that the uniform density of concrete, to take the conservation of heat storage method, in order to reduce the temperature difference between inside and outside elements, and strictly control the cooling rate of ℃ / d, for the concrete conditions of the creation of stress relaxation, is to prevent shrinkage cracks in concrete structures, one of the main measures。 (7) Construction of the summer heat must be cooled to control the concrete into the mold temperature shall not exceed 28 ℃ 。 the construction site should be shade measures to reduce the construction of temperature。 Winter construction with antifreeze to warm the specific measures, such as the concrete into the mold temperature above 5 ℃ , the thermal ponent to do the work too fast to prevent thermal cracks resulting from shrinkage. Underground construction of the development trend of increasing: ① type and scale. In recent years, some new, emerging types of underground construction. For example, with the growth of use of nuclear energy, nuclear waste handling and storage bee a serious problem。 in the deep strata (a few hundred meters to 1000 meters) in the construction of an underground nuclear waste repository is to solve this problem a better way to be a wide range of importance. In another example, the primary purpose of energy saving in the underground construction has developed rapidly。 At the same time, underground storage of heat, cold energy, mechanical energy (water, pressed air) and other aspects of the ongoing feasibility study and test. Again, in order to improve the urban environment, the ground floor of a largescale sewage treatment plants have been built in a small number of developed countries, the construction of urban waste disposal in the ground plant also being investigated. ② design and construction and continuously improved. The type of new construction is often 14 higher technical requirements, so that a new process development and improvement of construction technology. For example, in order to build a database of underground nuclear waste, it is necessary to solve the deep excavation of the postrock pressure and rock strata in the role of nuclear waste under the stress of high temperature change。 order to speed up the construction schedule is necessary to design and manufacture of largescale mining machinery。 in order to reduce project cost, it is necessary to adopt the new structure, high efficiency equipment and highstrength materials. ③ multidisciplinary research. The rapid development of underground construction, so that more and more people in different ways of living in the underground environment, and therefore meet the basic requirements based on the use of underground construction continuously higher quality requirements. From medicine, physiology, psychology and other disciplines, different perspectives, many ways to improve the underground environment of the ways and measures, including some of the more plex issue. For example, the underground environment and its impact on the dose of radioactive elements has been started to conduct research. ④ from individuals to groups, from single to prehensive development. Urban construction, to a certain stage of development, individual and scattered underground construction can not meet the various needs of urban life, is bound to gradually integrated to the groups and direction. For example, the Mass Transit Railway underground line to increase the formation of highspeed transportation work, the transfer line at different points on the formation of a relatively easy to change stations, car parks and shops, such as the underground plex, which may be expanded to bee the underground mall or mercial center . Also, in order to make full use of urban underground space should be to change the city39。s own utility system and the status of directburied 15 pipeline to make it to the layout and use of multifunction integrated pipeline corridor direction. To this end, calls for unity under the guidance of the overall urban planning, the development of urban underground space development and utilization of prehensive planning, and the same on the ground to unify urban development planning. 16 地下建筑結構 建造在巖層或土層中的建筑。它是現(xiàn)代城市高速發(fā)展的產(chǎn)物，起緩和城市矛盾，改善生活環(huán)境的作用，也為人類開拓了新的生活領域。人類合理開發(fā)和綜合利用天然形成的和人工挖掘的地下空間，不僅有助于緩和現(xiàn)代城市發(fā)展中的各種矛盾 ,改善生活環(huán)境 ,還為人類開拓了新的生活領域。由于地下建筑的大規(guī)模發(fā)展，地下建筑學正在形成，它的研究內(nèi)容包括地下建筑發(fā)展歷史和發(fā)展方向，地下空間的開發(fā)和利用，城市地下空間的綜合規(guī)劃，各類地下建筑的規(guī)劃設計，以及與地下建筑有關的環(huán)境、生理、心理和技術等問題。 地下建筑具有良好的防護性 能，較好的熱穩(wěn)定性和密閉性，以及綜合的經(jīng)濟、社會和環(huán)境效益。地下建筑處在一定厚度的巖層或土層中，可免遭或減少核武器、常規(guī)武器、化學武器和生物武器的破壞，同時也能較有效地抵御地震、颶風等自然災害。地下建筑的密閉環(huán)境和周圍存在著的比較穩(wěn)定的溫度場，對于創(chuàng)造恒溫或超凈的生產(chǎn)環(huán)境和在低溫或高溫狀態(tài)下貯存物資，防止污染，特別是對于節(jié)約能源，都是有利的。在城市中有計劃地建造地下建筑，對節(jié)省城市用地，降低建筑密度，改善城市交通，擴大綠地面積，減輕城市污染，提高城市生活質(zhì)量等方面，都可以起到重要的作用。地下建筑也有缺點，如 建筑成本高，施工復雜等。 地下建筑發(fā)展簡史 遠古時期，人類就開始利用天然洞穴防寒暑、避風雨和躲避野獸。在中國周口店發(fā)現(xiàn) ,50 多萬年前 ,北京猿人就居住在天然巖洞中。據(jù)仰韶文化和龍山文化遺址的考古發(fā)現(xiàn)，證明在距今 7000～ 5000 年前開始出現(xiàn)人工挖掘的居住洞穴，從簡單的袋形豎穴到圓形或方形的半地穴，上面有簡單屋頂。后來，開始在地面上建造住房，穴居逐漸不再是人類的主要居住方式。但古代陵墓仍然按照地上建筑方式在地下營建。有些糧倉也建在地下，如隋代洛陽的含嘉倉。中國西北、華北的黃土高原地區(qū)，由于 17 黃土地層便于挖 掘和氣候干燥，穴居的傳統(tǒng)一直延續(xù)至今。估計中國目前仍有