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电大岩土力学期末复习考试小抄名词解释岩石:岩石是组成地壳的基本物质,它是由矿物或岩屑在地质作用下按一定的规律聚集而成的自然体。地基承载力:地基所能承受荷载的能力土的渗透性:一般是指水流通过土中孔隙难易程度的性质。土的压缩性:土体在外荷载作用下体积减小的性质。固结:把空隙水从土体排出的过程称为固结。浅基础、深基础:一般埋置在5m以内,直接将荷载扩散分布于浅部地层,经简单施工方法筑成的称为浅基础。而深基础相对埋置深度大,其主要作用是把所承受的荷载相对集中地传递到地基深部。刚性基础、柔性基础:刚性基础:是指用抗压性能好,而抗拉、抗剪性能较差的砖、毛石、素混凝土以及灰土等材料修建的基础,又称无筋扩展基础。由钢筋混凝土材料建造的基础称为柔性基础,又称扩展基础。结构面:结构面是具有一定方向、延展较大、厚度较小的二维状地质界面。围岩:围岩指的是隧道周围一定范围内,对洞身的稳定有影响的岩(土)体。沉井基础:在深基础施工中,为保证开挖边坡稳定,并减少开挖土方工程量,利用一井筒形结构物,将其沉入地下并用作结构物的基础,称为沉井基础。地下连续墙:地下连续墙是利用专用的成槽机械开挖出一条狭长的深槽,槽内置放钢筋笼,灌注混凝土,使在地基中筑成连续的混凝土或钢筋混凝土墙体,具有支护、防渗、承重等多重功能。填空根据地质学的岩石成因分类可把岩石分为岩浆岩、沉积岩和变质岩三大类。结构面的分类:按其成因可分为:(1)原生结构面;再细分为、沉积结构面、火成结构面、变质结构面;(2)构造结构面;(3)次生结构面。岩石的蠕变分为稳定蠕变与不稳定蠕变两类。稳定蠕变:当岩石在较小的应力作用下,应变随时间增加而增加至某一值后,趋于稳定。不稳定蠕变:当岩石所受应力超过某一值时,应变随时间增加而增加,直至破坏用先期固结压力pc与现时的土压力p0的比值描述土层的应力历史,将粘性土进行分类1.正常固结土pcp0 2.超固结土pcp03.欠固结土 pcp0地基变形的三个阶段 :a.线性变形阶段;(塑性载荷pc) b.弹塑性变形阶段;(极限载荷pu) c.破坏阶段影响土压实性的主要因素:含水量、击实功能、土的种类和级配等土中的应力分类(按引起的原因):(1)由土本身有效自重在地基内部引起的自重应力;(2)由外荷(静荷载或动荷载)在地基内部引起的附加应力。地基的破坏形式 :1.整体剪切破坏;2.局部剪切破坏;3. 冲剪破坏。建筑物荷载通过基础作用于地基,对地基提出两个方面的要求:1.变形要求:建筑物基础在荷载作用下产生最大沉降量或沉降差,应该在该建筑物所允许的范围内 2.稳定要求:建筑物的基底压力,应该在地基所允许的承载能力之内。直接剪切试验方法:快剪 固结快剪 慢剪三轴剪切试验步骤: 1.装样;2.施加周围压力;3.施加竖向压力三轴试验方法:1.不固结不排水剪(UU)2. 固结不排水剪(CU)3. 固结排水剪(CD)洞室加固方法锚杆支护、衬砌及喷锚支护等。沉井的基本构造:常用的钢筋混凝土沉井主要由:刃脚、井壁、内隔壁、凹槽、封底及盖板等组成。简答Griffith 强度理论基本假设(1) 岩体内的裂隙形状是扁平的椭圆形; (2)相邻的裂隙不会互相影响;(3) 材料特性(如强度)的局部变化可以忽略;(4) 椭圆裂缝及其周围材料上的应力系统可作为二维问题处理。影响边坡稳定性的因素:影响边坡稳定性的因素有内在因素与外在因素两个方面。(1)内在因素有组成边坡岩土体的性质、地质构造、岩体结构、地应力等。它们常常起着主要的控制作用。(2)外在因素有地表水和地下水的作用、地震、风化作用、人工挖掘、爆破以及工程荷载等。其中地表水和地下水是影响边坡稳定最重要、最活跃的外在因素,其他大多起着触发作用。 郎肯土压力理论假定条件:墙体本身是刚性的;墙后填土水平并延伸到无限远;墙背竖直光滑库伦土压力理论假定条件:墙后填土为均匀的无粘性土(c=0),填土表面倾斜(0);挡土墙是刚性的,墙背倾斜,倾角为; 墙面粗糙,墙背与土体之间存在摩擦力(0);滑动破裂面为通过墙踵的平面。 朗肯理论和库伦理的共同点与不同点:共同点:朗肯理论和库伦理论均属于极限状态土压力理论。用这两种理论计算出的土压力均为墙后土体处于极限平衡状态下的主动土压力Ea和被动土压力Ep。不同点:朗肯理论从土体中一点的极限平衡状态出发,由处于极限平衡状态时的大小主应力关系求解(极限应力法);库伦理论根据墙背与滑裂面之间的土楔处于极限平衡,用静力平衡条件求解(滑动楔体法) 。沉井下沉过程中的主要问题及其处理方法:(1)沉井倾斜、偏移:倾斜和偏移是沉井施工过程中较为常遇见的问题,其原因有多种,如场地土层软硬不均、刃脚不平整、挖土不对称、沉井侧面受力不均匀或刃脚下局部有障碍物等。当沉井发生倾斜时可立即采取陶土法、不对称配重法、不对称射水法、水平向拉力扶正等措施。对于局部障碍物,应先进行人工排除后下沉。(2)停沉、下沉困难:导致停沉的原因主要有:1、开挖深度不足,阻力太大;2、发生偏斜;3、遇到障碍物或坚硬土层;4、井壁无有效减阻力措施 解决停沉的方法可以利用配重法、清障法等方法。(3)突然下沉:产生突然下沉的主要原因有:1、出现流塑土;2、挖土太深;3、排水迫沉。可以通过控制挖土深度,或临时增设底面支承装置解决。地下连续墙的适用范围:1、用作基坑支护结构, 可以与预应力锚杆或内支撑结构联合使用,也可以单独形成悬臂式地下连续墙。2、用作竖向承重结构,如地下室外墙、地铁站台、地下防渗墙等。地下连续墙的特点:1.墙体刚度大,可用作刚性基础;2.用于基坑维护工程,可以兼做挡土与止水,防渗效果好;3.施工过程振动小,噪音低,对环境影响小;4.适用于多种地基条件,可用于逆运作法施工;5.占地少、工效高。地下连续墙的施工过程: 施工前的准备: 有关作业面积、作业空间、场地地基的加固等内容。施工程序:地下连续墙的施工内容包括:准备工作、成槽工作、成墙工作、按工艺要求设置临时设施、修筑道路;在施工区域设置导墙;安装挖槽、泥浆制配、处理等机具设备;安装水电线路;进行试通水、通电、试运转、试挖槽、混凝土浇筑。现浇钢筋混凝土地下连续墙的施工工艺过程:(一)导墙施工(二)泥浆护壁(三)槽段开挖(四)钢筋笼加工和吊放(五)水下混凝土浇筑降水对周围地面的影响及预防措施:影响:降低地下水位时,由于土颗粒流失或土体压缩固结,易引起周围地面沉降。由于土层的不均匀性和形成的水位呈漏斗状,地面沉降多为不均匀沉降,可能导致周围的建筑物倾斜、下沉、道路开裂或管线断裂,因此,井点降水时,必须采取相应措施,以防造成危害。预防措施:1回灌井点法:该方法是在降水井点与需保护的建筑物、构筑物间设置一排回灌井点。在降水的同时,通过回灌井点向土层内灌入适量的水,使原建筑物下仍保持较高的地下水位,以减小其沉降程度。2设置止水帷幕法:在降水井点区域与原建筑之间设置一道止水帷幕使基坑外地下水的渗流路线延长,从而使原建筑物的地下水位基本保持不变。止水帷幕可结合挡土支护结构设置也可单独设置。常用的止水帷幕的做法有深层搅拌法、压密注浆法、冻结法等。3减缓降水速度法:减缓井点的降水速度,可防止土颗粒随水带出。具体措施包括:加长井点,调小离心泵阀门,根据土颗粒的粒径选择适当的滤网,加大砂滤层厚度等。基坑边坡稳定:基坑边坡的稳定,主要是靠土体的内摩阻力和粘结力来保持平衡的。一旦土体失去平衡,边坡就会塌方。边坡塌方会引起人身事故,同时会妨碍基坑开挖或基础施工,有时还会危及附近的建筑物。防止边坡塌方的措施:(1)放足边坡(2)设置支撑:常用的水平支撑方法:1)横撑式支撑:2)锚拉支撑:3)短柱横隔支撑4)钢板桩支撑:5)大型钢构架横撑:6)钢筋混凝土灌注桩支撑:7)土层锚杆支护:8)地下连续墙加锚杆支护: 请您删除一下内容,O(_)O谢谢!2016年中央电大期末复习考试小抄大全,电大期末考试必备小抄,电大考试必过小抄Basketball can make a true claim to being the only major sport that is an American invention. From high school to the professional level, basketball attracts a large following for live games as well as television coverage of events like the National Collegiate Athletic Association (NCAA) annual tournament and the National Basketball Association (NBA) and Womens National Basketball Association (WNBA) playoffs. And it has also made American heroes out of its player and coach legends like Michael Jordan, Larry Bird, Earvin Magic Johnson, Sheryl Swoopes, and other great players. At the heart of the game is the playing space and the equipment. The space is a rectangular, indoor court. The principal pieces of equipment are the two elevated baskets, one at each end (in the long direction) of the court, and the basketball itself. The ball is spherical in shape and is inflated. Basket-balls range in size from 28.5-30 in (72-76 cm) in circumference, and in weight from 18-22 oz (510-624 g). For players below the high school level, a smaller ball is used, but the ball in mens games measures 29.5-30 in (75-76 cm) in circumference, and a womens ball is 28.5-29 in (72-74 cm) in circumference. The covering of the ball is leather, rubber, composition, or synthetic, although leather covers only are dictated by rules for college play, unless the teams agree otherwise. Orange is the regulation color. At all levels of play, the home team provides the ball. Inflation of the ball is based on the height of the balls bounce. Inside the covering or casing, a rubber bladder holds air. The ball must be inflated to a pressure sufficient to make it rebound to a height (measured to the top of the ball) of 49-54 in (1.2-1.4 m) when it is dropped on a solid wooden floor from a starting height of 6 ft (1.80 m) measured from the bottom of the ball. The factory must test the balls, and the air pressure that makes the ball legal in keeping with the bounce test is stamped on the ball. During the intensity of high school and college tourneys and the professional playoffs, this inflated sphere commands considerable attention. Basketball is one of few sports with a known date of birth. On December 1, 1891, in Springfield, Massachusetts, James Naismith hung two half-bushel peach baskets at the opposite ends of a gymnasium and out-lined 13 rules based on five principles to his students at the International Training School of the Young Mens Christian Association (YMCA), which later became Springfield College. Naismith (1861-1939) was a physical education teacher who was seeking a team sport with limited physical contact but a lot of running, jumping, shooting, and the hand-eye coordination required in handling a ball. The peach baskets he hung as goals gave the sport the name of basketball. His students were excited about the game, and Christmas vacation gave them the chance to tell their friends and people at their local YMCAs about the game. The association leaders wrote to Naismith asking for copies of the rules, and they were published in the Triangle, the school newspaper, on January 15,1892. Naismiths five basic principles center on the ball, which was described as large, light, and handled with the hands. Players could not move the ball by running alone, and none of the players was restricted against handling the ball. The playing area was also open to all players, but there was to be no physical contact between players; the ball was the objective. To score, the ball had to be shot through a horizontal, elevated goal. The team with the most points at the end of an allotted time period wins. Early in the history of basketball, the local YMCAs provided the gymnasiums, and membership in the organization grew rapidly. The size of the local gym dictated the number of players; smaller gyms used five players on a side, and the larger gyms allowed seven to nine. The team size became generally established as five in 1895, and, in 1897, this was made formal in the rules. The YMCA lost interest in supporting the game because 10-20 basketball players monopolized a gymnasium previously used by many more in a variety of activities. YMCA membership dropped, and basketball enthusiasts played in local halls. This led to the building of basketball gymnasiums at schools and colleges and also to the formation of professional leagues. Although basketball was born in the United States, five of Naismiths original players were Canadians, and the game spread to Canada immediately. It was played in France by 1893; England in 1894; Australia, China, and India between 1895 and 1900; and Japan in 1900. From 1891 through 1893, a soccer ball was used to play basketball. The first basketball was manufactured in 1894. It was 32 in (81 cm) in circumference, or about 4 in (10 cm) larger than a soccer ball. The dedicated basketball was made of laced leather and weighed less than 20 oz (567 g). The first molded ball that eliminated the need for laces was introduced in 1948; its construction and size of 30 in (76 cm) were ruled official in 1949. The rule-setters came from several groups early in the 1900s. Colleges and universities established their rules committees in 1905, the YMCA and the Amateur Athletic Union (AAU) created a set of rules jointly, state militia groups abided by a shared set of rules, and there were two professional sets of rules. A Joint Rules Committee for colleges, the AAU, and the YMCA was created in 1915, and, under the name the National Basketball Committee (NBC) made rules for amateur play until 1979. In that year, the National Federation of State High School Associations began governing the sport at the high school level, and the NCAA Rules Committee assumed rule-making responsibilities for junior colleges, colleges, and the Armed Forces, with a similar committee holding jurisdiction over womens basketball. Until World War II, basketball became increasingly popular in the United States especially at the high school and college levels. After World War II, its popularity grew around the world. In the 1980s, interest in the game truly exploded because of television exposure. Broadcast of the NCAA Championship Games began in 1963, and, by the 1980s, cable television was carrying regular season college games and even high school championships in some states. Players like Bill Russell, Wilt Chamberlain, and Lew Alcindor (Kareem Abdul-Jabbar) became nationally famous at the college level and carried their fans along in their professional basketball careers. The womens game changed radically in 1971 when separate rules for women were modified to more closely resemble the mens game. Television interest followed the women as well with broadcast of NCAA championship tourneys beginning in the early 1980s and the formation of the WNBA in 1997. Internationally, Italy has probably become the leading basketball nation outside of the United States, with national, corporate, and professional teams. The Olympics boosts basketball internationally and has also spurred the womens game by recognizing it as an Olympic event in 1976. Again, television coverage of the Olympics has been exceptionally important in drawing attention to international teams. The first professional mens basketball league in the United States was the National Basketball League (NBL), which debuted in 1898. Players were paid on a per-game basis, and this league and others were hurt by the poor quality of games and the ever-changing players on a team. After the Great Depression, a new NBL was organized in 1937, and the Basketball Association of America was organized in 1946. The two leagues came to agree that players had to be assigned to teams on a contract basis and that high standards had to govern the game; under these premises, the two joined to form the National Basketball Association (NBA) in 1949. A rival American Basketball Association (ABA) was inaugurated in 1967 and challenged the NBA for college talent and market share for almost ten years. In 1976, this league disbanded, but four of its teams remained as NBA teams. Unification came just in time for major television support. Several womens professional leagues were attempted and failed, including the Womens Professional Basketball League (WBL) and the Womens World Basketball Association, before the WNBA debuted in 1997 with the support of the NBA. James Naismith, originally from Al-monte, Ontario, invented basketball at the International YMCA Training School in Springfield, Massachusetts, in 1891. The game was first played with peach baskets (hence the name) and a soccer ball and was intended to provide indoor exercise for football players. As a result, it was originally a rough sport. Although ten of Naismiths original thirteen rules remain, the game soon changed considerably, and the founder had little to do with its evolution. The first intercollegiate game was played in Minnesota in 1895, with nine players to a side and a final score of nine to three. A year later, the first five-man teams played at the University of Chicago. Baskets were now constructed of twine nets but it was not until 1906 that the bottom of the nets were open. In 1897, the dribble was first used, field goals became two points, foul shots one point, and the first professional game was played. A year later, the first professional league was started, in the East, while in 1900, the first intercollegiate league began. In 1910, in order to limit rough play, it was agreed that four fouls would disqualify players, and glass backboards were used for the first time. Nonetheless, many rules still differed, depending upon where the games were played and whether professionals, collegians, or YMCA players were involved. College basketball was played from Texas to Wisconsin and throughout the East through the 1920s, but most teams played only in their own regions, which prevented a national game or audience from developing. Professional basketball was played almost exclusively in the East before the 1920s, except when a team would barnstorm into the Midwest to play local teams, often after a league had folded. Before the 1930s very few games, either professional or amateur, were played in facilities suitable for basketball or with a perfectly round ball. Some were played in arenas with chicken wire separating the players from fans, thus the word cagers, others with posts in the middle of the floor and often with balconies overhanging the corners, limiting the areas from which shots could be taken. Until the late 1930s, all players used the two-hand set shot, and scores remained low. Basketball in the 1920s and 1930s became both more organized and more popular, although it still lagged far behind both baseball and college football. In the pros, five urban, ethnic teams excelled and played with almost no college graduates. They were the New York Original Celtics; the Cleveland Rosenblums, owned by Max Rosenblum; Eddie Gottliebs Philadelphia SPHAs (South Philadelphia Hebrew Association); and two great black teams, the New York Renaissance Five and Abe Sapersteins Harlem Globetrotters, which was actually from Chicago. While these teams had some notable players, no superstars, such as Babe Ruth, Jack Dempsey, or Red Grange, emerged to capture the publics attention as they did in other sports of the period. The same was true in college basketball up until the late 1930s, with coaches dominating the game and its development. Walter Doc Meanwell at Wisconsin, Forrest Phog Allen at Kansas, Ward Piggy Lambert at Purdue, and Henry Doc Carlson at Pittsburgh all made significant contributions to the games development: zone defenses, the weave, the passing game, and the fast break. In the decade preceding World War II, five events changed college basketball and allowed it to become a major spectator sport. In 1929, the rules committee reversed a decision that would have outlawed dribbling and slowed the game considerably. Five years later, promoter Edward Ned Irish staged the first intersectional twin bill in Madison Square Garden in New York City and attracted more than 16,000 fans. He demonstrated the appeal of major college ball and made New York its center. In December 1936, Hank Luisetti of Stanford revealed the virtues of the one-handed shot to an amazed Garden audience and became the first major collegiate star. Soon thereafter, Luisetti scored an incredible fifty points against Duquesne, thus ending the Easts devotion to the set shot and encouraging a more open game. In consecutive years the center jump was eliminated after free throws and then after field goals, thus speeding up the game and allowing for more scoring. In 1938, Irish created the National Invitation Tournament (NIT) in the Garden to determine a national champion. Although postseason tournaments had occurred before, the NIT was the first with major colleges from different regions and proved to be a great financial success. The National Collegiate Athletic Association (NCAA) created its own postseason tournament in 1939 but did not rival the NIT in prestige for some time. The 1940s saw significant changes for college basketball. Players began using the jump shot after Kenny Sailors of Wyoming wowed the East with it in 1943. The behind-the-back dribble and pass also appeared, as did exceptional big men. Bob Kurland at Oklahoma A&M was almost seven feet tall and George Mikan at DePaul was six feet ten inches. While Kurland had perhaps the better college career and played in two Olympics, he chose not to play professional ball, whereas Mikan became the first dominant star in the pros. Their defensive play inspired the rule against goal tending (blocking a shot on its downward flight). Adolph Rupp, who played under Phog Allen, also coached the first of his many talented teams at Kentucky in that decade. However, in 1951, Rupp and six other coaches suffered through a point-shaving scandal that involved thirty-two players at seven colleges and seriously injured college basketball, particularly in New York, where four of the seven schools were located. While the game survived, the NCAA moved its tournament away from Madison Square Garden to different cities each year and the NITs prestige began to decline. Professional basketball remained a disorganized and stodgy sport up until the late 1940s, with barnstorming still central to the game and most players still using the set shot. In 1946, however, hockey owners, led by Maurice Podoloff, created the Basketball Association of America (BAA) in the East to fill their arenas, but few fans came, even af

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