问题 问答题

(二)


[背景资料]
某施工总承包单位承担一项建筑基坑工程的施工,基坑开挖深度12m,基坑南侧距坑边6m处有一栋6层住宅楼。基坑土质状况从地面向下依次为:杂填土0~2m,粉质土2~5m,砂质土5~10m,黏性土10~12m,砂质土12~18m。上层滞水水位在地表以下5m(渗透系数为0.5m/d),地表下18m以内无承压水。基坑支护设计采用灌注桩加锚杆。施工前,建设单位为节约投资,指示更改设计,除南侧外其余三面均采用土钉墙支护,垂直开挖。基坑在开挖过程中北侧支护出现较大变形,但一直未被发现,最终导致北侧支护部分坍塌。事故调查中发现:
(1)施工总承包单位对本工程作了重大危险源分析,确认南侧毗邻建筑物、临边防护、上下通道的安全为重大危险源,并制订了相应的措施,但未审批。
(2)施工总承包单位有健全的安全制度文件。
(3)施工过程中无任何安全检查记录、交底记录及培训教育记录等其他记录资料。

该基坑坍塌的直接原因是什么从技术方面分析,造成该基坑坍塌的主要因素有哪些

答案

参考答案:该基坑坍塌的直接原因是采用土钉墙支护,垂直开挖。
从技术方面分析,造成该基坑坍塌的主要因素有:
(1)基坑(槽)开挖坡度不够,或通过不同土层时,没有根据土的特性分别放成不同坡度,致使边坡失稳而塌方。
(2)在有地表水、地下水作用的土层开挖时,未采取有效的降排水措施,土层湿化,内聚力降低,引起塌方。
(3)边坡顶部堆载过大,或受外力振动影响,使边坡内剪切应力增大,土体失稳而塌方。
(4)土质松软,开挖次序、方法不当而造成塌方。

阅读理解

阅读理解。

     People from other countries will find many different surprising things in Britain.

     Greek: A man from Greek sees a special way of driving in Britain. People drive on the left in the British street, but the British people never feel surprised. The Greek man said, "I've been in Britain for nearly a

month now. But at first, I couldn't always remember to drive on the left.  Every time, my friend reminded

me. "

     Japanese: Japanese people can't understand why British people keep their shoes on at home. In Japan, people walk in the room without shoes.If visitor keeps his shoes on at home in Japan,the Japanese people

think he is very impolite.

     Spanish: The Spanish people mind the way that the British people greet each other. They themselves

seem to be afraid of touching(接触). When they meet, they just smile or nod but never kiss or hug(拥抱)

in Spain.  But the British people think kissing is a very usual greeting when they meet!

     There is an old saying,"When in Rome, do as Romans do."When we go to a foreign country,we should follow the etiquette of the country.

1. The Greek visitor_______.

A. always drives on the left

B. used to drive on the left

C. drove correctly in Britain with his friend's help

2._______think it's impolite to wear shoes at home.

A. The Japanese

B. The Greek

C. The English

3. When greeting, the Spanish_______ .

A. kiss each other

B. hug each other

C. smile at each other

4. _______seem not to be afraid of touching each other.

A. The Spanish

B. The British

C. The Japanese

5. Etiquette in the world_______.

A. is the same

B. is important

C. is sometimes different and interesting

名词解释