问题 多项选择题

下列属于正台阶环形开挖法的有()。

A.开挖环形拱部

B.架立钢支撑、喷混凝土

C.开挖核心土和下台阶,随时接长钢支撑和喷混凝土、封底

D.一次衬砌作业

E.二次衬砌作业

答案

参考答案:A, B, C, E

解析:

正台阶环形开挖法的施工作业顺序为:用人工或单臂掘进机开挖环形拱部→架立钢支撑→喷混凝土。

在拱部初次支护保护下,为加快进度,宜采用挖掘机或单臂掘进机开挖核心土和下台阶,随时接长钢支撑和喷混凝土、封底。

根据初次支护变形情况或施工安排,实施二次衬砌作业。

阅读理解

阅读理解。

     Mark Twain, the famous American writer and a great master

of humor,liked to play jokes on others. But once a joke was played

on him. One day Mark Twain was invited to give a talk in a small

town. At lunch he met a young man,one of his friends.

     The young man said that he had an uncle with him. He told

Mark Twain that his uncle never laughed or smiled, and that

nobody and nothing was able to make his uncle smile or laugh.

      "You bring your uncle to my talk this evening," said Mark

Twain. "I'm sure I can make him laugh. "

     That evening the young man and his uncle sat in the front.

Mark Twain began to speak. He told several funny stories and

made everyone in the room laugh. But the man never even smiled.

Mark Twain told more funny stories, but the old man still kept

quiet. Mark Twain continued to tell his funny stories. Finally he

stopped. He was tired and quite disappointed.

     Some days later,Mark Twain told another friend what had

happened." Oh," said his friend, "I know that man. He's been

deaf for years. "

1. The writer wrote the passage mainly to _____.    

A. tell readers Mark Twain liked playing jokes

B. tell readers a joke played on Mark Twain

C. tell readers Mark Twain was a great writer

D. tell readers how to tell a funny story

2. One day Mark Twain met  _____  at lunch.

A. a friend                          

B. his brother

C. his teacher                        

D. a young girl

3.Why did Mark Twain ask the young man to bring his uncle to his talk?  

A. Because he thought he could make him laugh.

B. Because he wanted to get to know the old man.

C. Because the old man could tell stories.

D. because he wanted to learn from the old man.

4. Mark Twain stopped finally because he was _____.

A. disappointed        

B. sorry

C. ill                                        

D. sleepy

5. Mark Twain couldn't make the old man laugh because ____ .

A. his jokes were not funny

B. the old man wasn't interested in the jokes

C. the old man could tell more funny jokes

D. the old man was deaf

单项选择题