题目内容

背景资料
某港口工程预制沉箱混凝土设计要求的混凝土立方体抗压强度标准值为45MPa，经计算和试配优化，确定混凝土的配合比为1：1.15：2.68，混凝土的水胶比为0.40，高效减水剂的掺量为水泥重的0.7%0，AE引气剂的掺量为水泥重的0.08%，混凝土的含气量为4.0%。
问题
1.按规范规定，混凝土的施工配制强度应取多少？这时混凝土的施工强度≥设计要求的立方体抗压强度标准值的保证率为多少？
2.该混凝土的砂率为多少？（砂的相对密度为2.62，碎石的相对密度为2.65）
3.计算每立方米混凝土的各种材料用量。

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背景资料
南方某港地处潮汐河口的淤泥质地区，拟在已建码头的侧面扩建三个5万吨级的集装箱泊位，码头为重力式圆筒结构，港区道路及堆场建在吹填砂上。经设计方案比选，对道路及堆场区域的软基采取打排水板真空预压法进行处理。经过招投标，A施工单位承担了港区500万m3的吹填及10万m2的道路及堆场的施工任务。道路及堆场的典型设计断面如下图所示。
问题
1.列出真空预压法加固软土地基的工艺流程。
2.在对某真空预压的分区巡视检查中，发现该分区的真空度为50kPa，对此，施工单位应该怎样处理？按程序应该办理哪些手续？
3.若A施工单位为港口与航道工程施工总承包二级资质企业，能否承担该项目？说明理由。
4.该道路及堆场工程中应用了何种土工合成材料？其相应的功能是什么？
5.计算面层混凝土的施工配制强度(σ一3.5MPa)，并解释计算公式中各项参数的含义。

背景资料
某施工单位用耙吸式挖泥船开挖航道施工，航道中心至抛泥区的距离为15km，开挖航道长度3km，该船的舱容为5000m3，施工开挖的土质密度为1.85t／m3，耙吸船重载航速为9kn，轻载航速为11kn，挖泥时的航速为3kn，上线、抛泥、调头等用时间45min，因突发大风、潮水不适停止作业1.5h，避让航船30min。一次挖槽长度满舱载重量7000t，作业情况如图所示。
【问题】
1．计算该船的泥舱装载土方量。
2．如图所示，计算由A挖至B的抛泥施工循环运转生产率。
3．计算该挖泥船的时间利用率。

背景资料
某港的理论深度基准面与黄海平均海平面的高程差为2.0m，该港地形图中标注的港口港池泥面高程为一14.0m，某施工单位需通过港池拖运至安装地，沉箱拖运的最小稳定吃水为13m，沉箱拖运时的潮高为0.5m，富余水深按规范规定不得小于0.5m。
问题
1.沉箱拖运是否可行？计算水深说明理由。
2.如果拖运可行，潮高至少要多少米？在正常航速条件下，拖轮对沉箱的曳引作用点设在什么位置拖运最为稳定？
3.沉箱浮运拖带进行前，要进行哪些验算？ 4.沉箱在预制场下水有哪些方法？（举出三种方法）。

In January 2010 Ami took over an old warehouse with the intention of opening an art gallery. As the warehouse had to be converted, Ami entered into two contracts, one with Bry to do all the necessary plastering and one with Cis, who was to do all the necessary painting. Both Bry and Cis were to be paid ￡5,000. Both received initial payments of ￡1,000 and agreed to have the work completed on 31 March, as the art gallery had to be ready for its fi rst exhibition on 1 May.
At the end of February, Bry told Ami that he would not complete the plastering in time unless she agreed to increase his payment by a further ￡1,000. Ami agreed to pay the increased sum in order to ensure that the job was done on time. She then thought it was only fair that she should increase the amount of money promised to Cis by the same amount.
However, on completion of the work on time Ami refused to make either of the additional payments to Bry or Cis, beyond the original contractual price.
Required:
Advise Bry and Cis whether they have any rights in law to enforce Ami’s promise to pay them an extra ￡1,000.