问题 多项选择题

垫层的主要作用有:

A.提高地基承载力

B.减少沉降量

C.加速软弱土层的排水固结

D.防止冻胀

E.消除膨胀土的胀缩作用

答案

参考答案:A, B, C, D, E

解析:垫层的作用主要有: 1)提高地基承载力如果以抗剪强度较高的砂或其他填筑材料代替软弱的土,可提高地基的承载力,避免地基破坏 2)减少沉降量由于砂垫层或其他垫层对应力的扩散作用,使作用在下卧层土上的压力较小,这样也会相应减少下卧层的沉降量。 3)加速软弱土层的排水固结垫层可作为良好的排水面,可以使基础下面的孔隙水压力迅速消散,加速垫层下软弱土层的固结和提高其强度,避免地基土塑性破坏。 4)防止冻胀因为粗颗粒的垫层材料孔隙大,不易产生毛细管现象,因此可以防止寒冷地区中结冰所造成的冻胀。这时,砂垫层的底面应满足当地冻结深度的要求。 消除膨胀土的胀缩作用在膨胀土地基上可选用砂、碎石、块石、煤渣、二灰或灰土等材料作为垫层以消除胀缩作用,但垫层厚度应依据变形计算确定,一般不少于0.3m,且垫层宽度应大于基础宽度,而基础的两侧宜用与垫层相同的材料回填。

单项选择题 A3/A4型题
阅读理解

Shopping is not as simple as you may think! There are all sorts of tricks at play each time we reach out for that particular brand (商标) of product on the shelf.

Colouring, for example, varies according to what the producers are trying to sell. Health foods are packaged (包装) in greens, yellows or browns because we think of these as healthy colours. Ice cream packets are often blue and expensive goods, like chocolates, are gold or silver.

When some kind of pain killer was brought out recently, researchers found that the colours turned the customers off because they made the product look weak and ineffective. Eventually, it came on the market in a dark blue and white package—blue because we think of it as safe, and white as calm.

The size of a product can attract a shopper. But quite often a bottle doesn’t contain as much as it appears to.

It is believed that the better-known companies spend, on average, 70 per cent of the total cost of the product itself on packaging!

The most successful producers know that it’s not enough to have a good product. The founder of Pears soap, who for 25 years has used pretty little girls to promote(推销)  their goods, came to the conclusion: “Any fool can make soap, but it takes a genius (天才) to sell it.”

小题1:Which of the following may trick a shopper into buying a product according to the text?

A.The cost of its package.

B.The price of the product.

C.The colour of its package.

D.The brand name of the product.小题2:The underlined part “the colours turned the customers off”(in Para. 3 ) means that the colours _____.

A.attracted the customers strongly

B.had weak effects on the customers

C.tricked the customers into shopping

D.caused the customers to lose interest小题3:Which of the following is the key to the success in product sales?

A.The way to promote goods.

B.The discovery of a genius.

C.The team to produce a good product.

D.The brand name used by successful producers.小题4:Which of the following would be the best title for this text?

A.Choice of Good Products

B.Disadvantages of Products

C.Effect of Packaging on Shopping

D.Brand Names and Shopping Tricks