砂垫层、填砂技术交底.doc

交底内容：
一、碎石垫层施工
粉喷桩施工完成28天，并经检测合格后，在其上铺30cm厚级配碎石垫层，碎石最大粒径不宜大于3cm。
二、砂垫层施工
1、碎石垫层施工完毕后，在上面铺一层40型双向土工格栅，土工格栅双向抗拉强度不小于40KN/m，断裂延伸率小于10%，其连接采用铅丝绑扎，搭接宽度不小于0.1m。在其上铺20cm中粗砂垫层。
2、材料应具有良好的透水性，不含有机质、粘土块、和其它有害物质的中粗砂，其中粒径小于0.074mm颗粒含量应不大于3%,有机物含量不大于1%，做好各项技术指标的材料试验。
3、必须按照施工图纸的厚度0.2m铺筑辗压，砂垫层伸出路堤坡脚外1m。
4、砂垫层应按图纸要求做成横坡，以便横向排水、渗透，断面尺寸不能小于设计值，按每200m检查4处的方法进行检查。
三、填砂施工
1、砂垫层处理完后经监理工程师签证同意进行下道工序即填砂施工时，应立即组织人员机械进行施工。
2、应采用分层填筑，分层填筑的厚度一般不大于30cm。
3、填砂过程中预埋好沉降观测设施，观测沉降量、速率、水平位移，做好原始记录，确定每一层的合理填土高度和填筑速率。
4、 地面横坡不陡于1：5时，可及时进行下道工序施工。
5、填筑路的过程中，应严格控制填料的压实度。应满足：机动车道路槽底0~80cm范围内不小于93%，路槽底80cm以下不小于90%。
Cards on the table contents:
First, construction of gravel cushion
Pile Construction completed 28 days and tested after passing grade in his upper berth with 30cm thick gravel pads, the largest stone size should be less than 3cm.
Second, construction sand cushion
1, after completion of construction gravel cushion in the top layer of 40-type two-way geogrid, geogrid tensile strength of not less than two-way 40KN / m, elongation of less than 10%, its connection with wire banding, lap width of not less than 0.1m. 20cm in the coarse sand in its upper berth cushion.
2, material should have good water permeability, non-organic matter, clay blocks, and other harmful substances in the coarse sand, which is less than 0.074mm particle size should not exceed 3% of the content, organic matter content of less than 1% various technical indicators do materials testing.
3, the construction drawings must be in accordance with the thickness of 0.2m paved rolling, out of sand cushion foot embankment outside the 1m.
4, sand cushion made of cross slope requirements shall be drawing to horizontal drainage, infiltration, cross section size not less than the design value, 4 per 200m inspection methods to be checked.
Third, the construction of sand fill
1, sand cushion has been dealt with by the supervising engineer visa agreed that the next process sand filling works, should immediately organize personnel to conduct construction machinery.
2, should be stratified filling, filling the thickness of the layer does not exceed 30cm.
3, the process of filling sand embedded good settlement observation facilities, observation settlement, rate, horizontal displacement, good original records to determine the filling height of each layer and filling a reasonable rate.
4, the ground cross slope is not steep at 1:5, can be timely construction of the next process.
5, the process of filling the road, should strictly control the degree of compactness. Should be met: 0 ~ 80cm bottom road vehicle within not less than 93%, Road bottom 80cm of not less than 90% less.