
胶结洞挖石渣在东庄围堰工程中的适用性研究
王民侠, 王健, 王云涛, 付登辉
胶结洞挖石渣在东庄围堰工程中的适用性研究
Research on the Suitability of Cemented Excavated Gravel in the Dongzhuang Cofferdam Project
东庄水库上游围堰有效填筑时间为3个月。由于地形地质条件限制,当地材料围堰布置困难,围堰型式在碾压混凝土和胶结砂砾料中进行比选,胶结骨料考虑了人工骨料和洞挖石渣料两种方案。胶结人工骨料围堰由于断面较大,人工骨料单价较高,投资与碾压混凝土围堰基本相当;采用洞挖石渣料作为骨料可减少破碎筛分工序及弃渣处理费用,大大降低工程投资。经七组级配试验表明,大于300 mm粒径含量为1.9%~15.3%,大于200 mm粒径含量为5.2%~28.3%,使洞挖石渣料作为胶结骨料成为可能。经八组配合比试验验证,试件28天抗压强度均在11 MPa以上,远超设计强度4 MPa,可通过降低胶凝材料用量、调整水灰比进一步优化配合比设计。采用洞挖石渣料替代砂砾料或人工骨料修建胶凝材料围堰工程满足设计要求,具有减少弃渣、利于环保、构造简单、施工便捷、安全经济的优势,可降低投资达40%左右。
The cofferdam of the upstream of Dongzhuang Reservoir has to be filled in three months. Due to the limitation of topographical and geological conditions, it is difficult to construct cofferdams with local materials. The type of cofferdam is selected between RCC and CSG. Two options are considered for the selection of cemented aggregate: artificial aggregate and excavated gravel. Due to the large cross-section of the cemented artificial aggregate cofferdam, the unit cost of artificial aggregate is high and the investment is basically the same as that of the RCC cofferdam. Using excavated gravel as aggregate can shorten the process of crushing and screening and the cost of waste gravel disposal, greatly reducing the project investment. Seven sets of grading tests have shown that the particle size content of greater than 300 mm is 1.9% to 15.3%, and the particle size content of greater than 200 mm is 5.2% to 28.3%, which makes it possible to use the excavated gravel as cementitious aggregate. After eight group proportioning tests, the compressive strength of the specimens is more than 11 MPa in 28 days, far exceeding the design strength of 4 MPa, which can be further optimized by reducing the amount of cementitious material and adjusting the water-cement ratio. It is the first of its kind in China to use excavated gravel instead of natural gravel or artificial aggregate to construct cofferdam of cemented material to meet design requirements, with the advantages of waste residue reduction, environmental protection, simple structure, convenient construction, safety and economy, which reduces investment by up to 40%.
胶结洞挖石渣 / 围堰工程 / 选型 {{custom_keyword}} /
cemented excavated gravel / cofferdam / type selection {{custom_keyword}} /
表1 围堰型式分析比较表Tab.1 Cofferdam type analysis and counting table |
项目 | 型式 | |
---|---|---|
碾压混凝土围堰 | 胶结洞挖石料围堰 | |
建筑材料 | 利用开挖石料加工人工混凝土骨料,细骨料利用开挖石料 制砂。 | 利用洞挖石渣料作为骨料,细骨料利用开挖石料制砂。 |
施工辅助企业 | 需在坝址上游设置砂石加工系统和混凝土拌和系统,系统规模较胶结人工砂石坝低。 | 需在坝址上游设置混凝土拌和系统,混系统规模较大。 |
碾压上料施工方法 | 混凝土在低位采用自卸汽车入仓,高位采取溜槽入仓,平仓机平仓,振动碾碾压,机械化水平高。 | 混凝土在低位采用自卸汽车入仓,高位采取溜槽入仓,平仓机平仓,振动碾碾压,机械化水平高。 |
温控措施 | 水泥用量较多,温控措施简单,温控费用较低。 | 水泥用量少,无温控措施要求,无温控费用。 |
施工工期 | 基础及边坡处理要求较高,工期3个月。 | 基础及边坡处理简单,工期2.5个月。 |
节能环保 | 开挖料按照人工骨料要求进行破碎筛分,相对耗能高 | 洞挖石渣料简单筛除超径料,相对耗能较低 |
投资 | 4 337 万元 | 2 572 万元 |
表2 洞挖石渣料湿筛试件试验结果表Tab.2 Test results of wet sieve specimens for excavated gravel |
编号 | 水泥/(kg·m-3) | 粉煤灰/(kg·m-3) | 用水量/(kg·m-3) | VC值/s | 砂率/% | 抗压强度/MPa |
---|---|---|---|---|---|---|
28 d | ||||||
DZA80 | 40 | 40 | 90 | 14 | 35 | 11.1 |
DZA100 | 50 | 50 | 100 | 5 | 14.3 | |
DZA110 | 55 | 55 | 105 | 2 | 15.4 | |
DZB80 | 40 | 40 | 85 | 7 | 25 | 11.4 |
DZB100 | 50 | 50 | 95 | 3 | 13.1 | |
DZB110 | 55 | 55 | 100 | 3 | 14.3 | |
DZC80 | 40 | 40 | 80 | 5 | 18 | 11.0 |
DZC110 | 55 | 55 | 90 | 3 | 11.7 |
表3 围堰荷载作用组合表Tab.3 Cofferdam coaxial action combination table |
主要考虑情况 | 作用类别 | ||||
---|---|---|---|---|---|
自重 | 静水压力 | 扬压力 | 浪压力 | 泥沙压力 | |
设计洪水情况 | √ | √ | √ | √ | √ |
施工完建情况 | √ |
表4 围堰抗滑稳定计算成果表Table 4 Calculation results of anti-sliding stability of cofferdam |
计算工况 | 抗剪断安全系数K′ | 坝踵竖向正应力/MPa | 坝趾竖向正应力/MPa | 坝踵最大主压应力/MPa | 坝趾最大主压应力/MPa | |
---|---|---|---|---|---|---|
K′ | [K′] | |||||
设计洪水位 | 4.03 | 3.0 | 0.22 | 0.96 | 0.76 | 1.30 |
施工期 | ∞ | 2.5 | 0.74 | 0.62 | 0.93 | 0.84 |
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