2016年广播电视大学岩土力学形成性考核册考核作业1-4参考答案小抄.doc

岩土力学 岩土力学 作业一说明：本次作业对应于文字教材1至3章，应按相应教学进度完成。一、填空题 （每空1分，共计25分）1工程上常用的土的密度有湿密度、饱和密度、浮密度和干密度。 2土是由 固相 、 气相 、和 液相 三部分组成。3土体的应力按引起的原因分为 自重应力 和 附加应力 两种。4对于天然土，ocr1时的土是 超固结土 ，ocr=1的土属于 正常固结土 ，而ocr1=300kpa或3=140.2kpa 所以不会剪破。某挡土墙高8m，墙背竖直光滑，填土面水平，填土为无粘性土，=18kn/m3，=30，填土表面作用有连续均布荷载，q=20kpa。试用朗肯土压力理论计算主动土压力以及作用点位置。解 （1）土压力系数（2）主动土压力墙顶 pa=qka=201/3=6.7kpa墙底 pa=qka+rhka=6.7+1881/3=54.7kpa总土压力pa=（6.7+54.7）/28=245.6kn/m作用点距墙底的距离 在均布条形荷载作用下，土体中a点的大主应力1=400kpa中，小主应力3=150kpa，土的抗剪强度指标c=0，=30。试求：1) a点处土是否处于极限平衡状态。最危险的剪应力面与最大主应面夹角为多少度？ 解：1）133kpa150kpa 处于稳定状态2）最危险的剪应力面与最大主应面夹角60（10分）4有一条形基础，宽度b为6m，埋深d为1.5m，其上作用着中心荷载p为1700kn/m，地基土质均匀，容重为19kn/m3，土的强度指标为：c=20kpa，=20o，安全系数为2.5，假定基底完全粗糙，应用太沙基理论，验算地基的稳定性 (=20o时，)。（10分）解：（1）基底压力为：p=p/b=1700/6=283.3kpa(2) 由太沙基理论，地基的极限承载力为=1963.5/1+191.56.5+2015=684.8kpa(3) 容许承载力为=684.8/2.5=273.9kpa由于：pf，地基不稳定。岩土力学 作业三说明：本次作业对应于文字教材7至9章，应按相应教学进度完成。一、单项选择题 （每小题2分，共计10分）1岩石内结晶晶格错位的结果，引起岩石的 （b） a、晚性破坏 b、塑性破坏 c、弱面剪切破坏2岩石的单轴抗压强度一般与单轴抗拉强度间成下列哪种关系： (b)a.rc=(1-4)rtb. rc=(4-10)rt c. rt=(1-4)rc d. rt=(1-4)rc 3下面岩体的那种应力状态是稳定状态 (a)a. sinc. =sin4.广义虎克定律中岩石的剪切模量g为 （a）a. ，b. ，c. ，d. 5. 岩石的变形（弹性）模量可表示为 （c）a. ，b.，c.，d.二、填空题 （每空1分，共计20分）1岩石的破坏形式：脆性破坏、延性破坏、弱面剪切破坏。2岩石的力学强度是工程设计中最重要的力学指标，分别是单轴抗压强度，抗拉强度、抗剪强度。3岩石的抗压强度就是岩石试件在单轴压力（无围压）作用下，抗压破坏的极限能力。4岩石的抗剪强度就是指岩石抵抗剪切破坏（滑力）的能力，用凝聚力c和内摩擦角来表示。5 岩石的变形是指岩石在任何物理因素作用下形状和体积大小的变化。岩石的变形特性常用弹性模量e和泊松比两个指标来表示；6. 岩石的蠕变是指岩石在应力不变的情况下岩石变形随着时间t而增加的现象，一般而言，典型的岩石蠕变曲线可分为三个阶段：初期蠕变，二次蠕变（稳态蠕变），（加建蠕变）第三期蠕变。7. 天然应力(或初始应力)是习惯上常将工程施工前就存在于岩体中的地应力，称为初始应力。8. 岩滑根据滑动面的形式，组合可分为：平面滑动，楔形滑动和旋转滑动。三、判断题 （每小题2分，共计10分）1岩石的脆性破坏是由于岩石中裂隙的发生和发展的结果所致（）2岩石的变形是指岩石在外力作用下形状和大小的变化。（）3最大正应变理论是用来判断脆性岩石破坏的理论。（）4根据莫尔库伦准则可证明均质岩石的破坏面法线与大应力方向间夹角为（） 5在普通压力板上做岩石的变形试验，即可得到岩石的全应力-应变曲线。（）四、问答题 （每小题5分，共计20分）1何为塑性破坏，其破坏机理是个什么？答案：塑性破坏(延性破坏)是岩石在破坏之前变形量很大，且没有明显的破坏荷载。原因可能是岩石内结晶晶格错位的结果。2影响单轴抗压强度的因素有哪些？影响单轴抗压强度的因素有：一方面是岩石材料本身的，一方面是试验方法上的因素。 岩石材料本身的主要因素有：矿物组成；结晶程度和颗粒大小；胶结情况；生成条件；风化作用；密度；水的作用等。试验方面的因素有：试件尺寸和大小；加荷速度等。3. 直剪破坏试验全过程曲线可分几段？各区段的特点是什么？岩石直剪破坏试验全过程曲线如图所示该曲线共分三段。第一段：原点p区段，该段近似为一直线即变形为弹性，p为极限强度(即裂隙开始发展的强度)；第二段：p f区段，f为峰值强度，该段内裂隙发展至破坏；第三段：fo区段。o为剪断面上的摩擦力(剩余强度)4. 什么叫滑坡？滑坡滑动面的形式有几种 当岩坡受力过大或岩石强度过低，一部分岩体向下或向外滑动叫滑坡，滑波滑动面有三种：软弱结构面；结构面；在岩体中；六、计算题 （每题10分，共计40分）1将一个岩石试件进行单轴试验，当压应力达到120mpa时即发生破坏，破坏面与大主应力平面的夹角(即破坏所在面与水平面的仰角)为60，假定抗剪强度随正应力呈线性变化(即遵循莫尔库伦破坏准则)，试计算：1)内摩擦角：2)破坏面上的正应力和剪应力。解： = ，理论上的抗拉强度：2某岩样c=15kpa，=30，如该土受到最小主应力3=200kpa，最大主应力1=400kpa，试判断该土样处于何种状态？解： (不稳定)3试求证。解： 代入即求4岩石试件的单轴抗压强度为160mpa，泊松比。岩石试件在三轴试验中破坏，破坏时的最小主应力为130mpa，中间主应力为260mpa，根据最大正应变理论的破坏准则，推算这时的最大主应力。解： 岩土力学 作业四说明：本次作业对应于文字教材10至12章，应按相应教学进度完成。一、填空题 （每空分，共计30分）1把由于洞室围岩的变形和破坏作用而作用在支护或衬砌上的压力称为山岩压力。2山岩压力的影响因素除岩石性质外，还应考虑洞室的形状和大小，地质构选，支护的形式和刚度、洞室深度、时间、施工方法等因素。3.地下工程岩体稳定性影响因素主要有岩土性质、岩体结构与地质构造、地下水、地应力及地形等。3岩基的极限承载力，就是指岩基所能负担的最大荷载(或称极限荷载)。4脆性围岩的变形破坏类型有张裂坍落、劈裂、剪切滑动或破坏、岩爆、和弯折内鼓。5大坝失稳的形式主要有：表层滑动破坏、深层滑动破坏、混合滑动破坏。6. 由于岩体变形而对支护或衬砌的压力，称为变形压力；将由于岩体破坏而而对支护或衬砌的压力，称为松动压力。7. 在中等质量的岩石中，洞室围岩的变形较大。由于洞室围岩的应力重分布需要一定的时间，所以在进行支护或衬砌以后围岩的变形受支护或衬砌的约束，于是产生山岩压力。8. 在整体性良好，裂隙节理不发育的坚硬岩石中开挖洞室，开挖结束后，围岩的弹性变形就完成。若在此后进行支护，支护没有山岩压力。这种支护主要是用来防止岩石的风化以及剥落碎块的掉落。9.无裂隙围岩的应力计算方法有内应力分配法和抗力系数法。三、判断题 （每小题2分，共计10分）1求解山岩压力的计算理论中，太沙基理论把岩体假定为散粒体。 （ ）2由于洞室围岩的变形和破坏而作用于支护或衬砌上的压力称为围岩压力。（ ）3围岩处于塑性变形状态时，洞室埋置愈深，山岩压力愈大。 （ ）4开挖洞室的影响范围是6倍洞直径。 （）5.洞室的形状相同时，围岩压力与洞室的尺寸无关。 （ ）四、问答题 （每小题5分，共计20分）1.简述地下洞室开挖引起的围岩应力重分布及其规律教材283页2何为山岩压力？按其成因可分为哪几类？各自用什么方法确定？把由于洞室围岩的变形和破坏而作用在支护或衬砌上的压力称为山岩压力。 由于围岩变形而作用在支护或初砌上的岩压力称为变形压力。称为变形压力。 由于围岩破坏而作用在支护或初砌上的岩压力称为变形压力。称为松沙压力。 计算变形压力的方法：弹塑理论推导出的芬纳公式或修正芬纳公式。 计算松动压力的方法：压力拱理论，太沙基理论和弹塑性理论推出卡柯公式。3不同质量状况的围岩变形破坏特别如何？ 整体性良好，裂隙不发育的坚硬岩石中，围岩应力小于围岩强度无破碎。变形以开挖过程中的弹性变形为主，开挖结束变形也结束。如果支护，支护上一般无山岩压力，支护起防止岩石风化或剥落碎块的掉落。 中等质岩的岩体，洞室变形大，还可能有少量破碎，支护上以变形压力为主，松动压力为辅。 在破碎和软弱岩石中，岩体强度低，被切割的很碎，围岩应力超过岩体强度很多，因此，岩块在不大的应力作用就会破坏坍落，在这类岩石中，坍落和松动是产生山岩压力的主要原因。4.简述高压固结灌浆的施工方法。教材344347五、计算题 （每题10分，共计40分）1埋深200m处的岩体内开挖一硐径为2a=2m圆形断面隧道，如果岩体中初始地应力为静水压力式，并且上覆岩层的平均容重为g/cm3，若隧道周岩的抗剪强度指标mpa，试用莫尔-库仑强度条件评价其硐壁的稳定性。解： 洞壁：1=2z 3=0 (不稳定)2在地下50m深度处开挖一地下洞室，其断面尺寸为5m5m。岩石性质指标为：凝聚力c=200kpa，内摩擦角，容重=25kn/m3，侧压力系数。已知侧壁岩石不稳，试用太沙基公式计算洞顶垂直山岩压力及侧墙的总的侧向山岩压力。解： 这时， 3某圆形洞室围kn/m3，埋置深度h=160m，洞的半径r0=7m。设折减扣的凝聚力c=0.02mpa，求松动压力。 系数k1曲线 系数k2曲线 解 mpa ，则由查图6-16和图6-17的曲线得：所以mpa4.有压隧洞的最大内水压力=2.8mpa，隧洞(内)半径为2.3m，用厚度为0.4m的混凝土衬砌。已知混凝土的弹性模量=1.8104mpa，泊松比。岩石的弹性模量=1.1104mpa，泊松比=0.367。试求： 1)离中心2.5m处的衬砌内的应力；2)离中心3.5m处的围岩附加应力。解：a=2.3m，b=2.7m，p=2.8mpa。将已知的、以及a和b值代入式(7-25)，得： 所以混凝土衬砌传给岩石的压力为：mpa求离中心3.5m（）处的围岩附加应力：mpampa 要求衬砌内任何点()的应力、则可根据厚壁圆筒的公式计算：2.5 (压应力) (拉应力) 在衬砌的周界上，当时，有：当时，有：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