问题 单项选择题

某两个场地,建筑设防烈度8度,设计地震分组第一组,A场地:0~9m粉质黏土,υs=180m/s;9~12m粉砂,υs=300m/s;12m以下为基岩。B场地:0~3m黏土,υs=150m/s;3~12m粉质黏土,υs=225m/s;12~15m粉砂,υs=300m/s。判别A、B场地特征周期大小。()

 

A.TgA=TgB

B.TgA>TgB

C.TgA<TgB

答案

参考答案:A

解析:

A场地覆盖层厚度12m,B场地覆盖层厚度15m,

A、B场地均为Ⅱ类,A、B场地特征周期TgA=TgB=0.35s。

点评:场地特征周期和场地类别有关,场地类别和等效剪切波速有关,其Vse和覆盖层厚度有较大的变化范围,所以A和B场地虽然覆盖厚度不一样,但都在变化的范围中,场地类别一样,其特征周期相同。

写作题
阅读理解

There are three separate sources of danger in supplying energy by nuclear power(原子能).

First, the radioactive material must travel from its place of production to the power station. Although the power stations themselves are strongly built, the containers used for the transport of the materials are not. Normally, only two methods of transport are in use, namely road or rail. Unfortunately, both of these may have an effect on the general public, since they are sure to pass near, or even through, heavily populated areas.

Second, there is the problem of waste. All nuclear power stations produce wastes that in most cases will remain radioactive for thousands of years. It is impossible to make these wastes nonradioactive, and so they must be stored in one of the inconvenient ways that scientists have invented. For example, they may be buried under the ground, or dropped into deserted mines, or sunk in the sea. However, these methods do not solve the problem, since an earthquake could easily break the containers.

Third, there may occur the danger of a leak(泄漏) or an explosion at the power station. As with the other two dangers, this is not very likely, so it does not provide a serious objection to the nuclear program. However, it can happen.Separately, these three types of dangers are not a great cause for worry. Taken together, though, the probability of disaster(灾难) is extremely high.

1.Which of the following is FALSE?

A.It is possible that a leak or an explosion occurs at a power station.

B.It is unusual for radioactive materials to be transported across land.

C.The containers are likely to be broken by an earthquake.

D.Nuclear wastes remain dangerous in most cases for many years. 

2.The author thinks that the ways to store nuclear wastes are ________.

A.easy      B.impossible         C.reasonable        D.ineffective 

3.What do we learn from the last paragraph?

A.The power station is a safe place.

B.The dangers of nuclear energy can be prevented.

C.The general public are strongly against the nuclear program.

By itself, none of the three dangers is very likely to cause much worry.

4.What is this passage about?

A.Uses of nuclear power.          B.Dangers from nuclear power.        

C.Public anger at nuclear power.  D.Accidents caused by nuclear power.