问题 单项选择题

根据地形和水流条件,涵洞的洞底纵坡应为12%,此涵洞的基础应()。

A.做成连续纵坡 

B.在底部每隔3-5m设防滑横墙 

C.做成阶梯形 

D.分段做成阶梯形

答案

参考答案:D

解析:

洞底应有适当的纵坡,其最小值为0.4%,一般不宜大于5%,特别是圆管涵的纵坡不宜过大,以免管壁受急流冲刷。当洞底纵坡大于5%时,其基础底部宜每隔3~5m设防滑横墙,或将基础做成阶梯形;当洞底纵坡大于10%时,涵洞洞身及基础应分段做成阶梯形,而且前后两段涵洞盖板或拱圈的搭接高度不得小于其厚度的1/4,如图所示。

阶梯形涵洞洞身

阅读理解

阅读理解

     The wellknown Rushmore National Monument in the United States is built on the Rush Moore Peak,

1829 meters above sea level, of the Black Hills in the south-west of South Dakota.It is a group of huge

stone statues of four American presidents, George Washington, Thomas Jefferson, Abraham Lincoln

and Theodore Roosevelt.President Washington is the founding father of the country; the 3rd President

Jefferson drafted the US Declaration of Independence; the 16th President Lincoln issued the

Emancipation Proclamation and the 26th President Roosevelt protected the average people's right to

compete fairly with trusts.All 1829 meters above sea level, made outstanding achievements for their

country.They were pioneers of US history.

     The stone statues of presidents were built at the suggestion of a historian in the State of Dakota, with

a view to carrying forward the US pioneering spirit everlastingly.

     The statues are 18 meters high.They are the highest and greatest realistic stone statues in the world,

taller than a 6storied building and larger than the Great Sphinx of Egypt.The size of each head is 20sq

mt, with a 20meterlong face, a 7meterlong nose, a 2.6meterwide mouth and two 1.5meterwide eyes.

Though not facing the same direction, they are all lifelike and look ahead gravely in harmony with fixed

gazes.On clear days, one can have a sight of the four presidents with their firm and steady expression at

a distance of dozens of kilometers.

     Since the stone sculpture is unique in style, the Monument is now the US National Art Centre of

Popular Education.Groups of people keep streaming everyday to the site for a visit and tourists across

the world are also interested in taking a view of this great Monument.

1. Which statement is false according to the first paragraph?

A. The famous Rushmore National Monument is 1829 meters above sea level.

B. All the four presidents made great contributions to London.

C. the group of statues are made of huge stones.

D. The statues are built to honor the presidents in the US

2. Why were those four presidents chosen?Because the four presidents________.

A. made great contributions to their country

B. were pioneers of US history

C. played an important role in the different periods of the American history

D. all of the above

3. What are the statues like?

A. They look like a 6storied building.

B. They are like the great Sphinx of Egypt.

C. They are like true men standing there.

D. They are lifelike, looking ahead with fixed gazes.

4. For what groups of people across the world come to visit the Monument?They come________.

A. to learn the US pioneering spirit

B. to look back upon the history of the US.

C. to learn the art of sculpture

D. to enjoy the view of the Monument

选择题