砂卵石地层土压平衡盾构施工渣土改良试验
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摘要
砂卵石地层土压平衡盾构施工时需进行渣土改良,提高渣土的流塑性.针对成都砂卵石地层采用泡沫、膨润土和聚合物进行改良,进行室内塌落度试验、搅拌试验和泥浆黏度试验来确定配比.研究结果表明,钠基膨润土比钙基膨润土具有更好的膨化能力,且不发生分层,更适用于渣土改良.案例中膨润土单独改良的合理配比为泥浆质量分数14.3%,注入量体积比20%.泡沫改良时注入率受渣土含水率影响较大,土体含水率越大,泡沫最佳注入率越小.泡沫加膨润土共同改良比两者单独改良效果要好,选择泡剂质量分数为3%、泥浆质量分数为14.3%,添加量在某一个范围,有多种组合都可以满足要求;当泥浆注入量体积比为12%时,泡沫最优注入量体积比为15%～20%;当泥浆注入量体积比为6%,泡沫最优注入量体积比为30%～35%.当地下水丰富时,需要添加聚合物;正常情况下也可降低膨润土泥浆浓度,添加聚合物,来节省膨润土用量,从而降低工程成本.
Soil conditioning is used to improve the plastic flow capacity of earth pressure balance(EPB) in sandy cobble strata. Conditioning tests were conducted for sandy cobble strata in Chengdu by using foam, bentonite, and polymer, including the slump test, the stirring test as well as the viscosity test. The results show that sodium bentonite has a better bulking capacity than Ca-bentonite and is not layered, which is more suitable for soil conditioning. The reasonable ratio for bentonite alone is to have a concentration of 14.3% and an injection rate of 20%. The foam injection rate is influenced by soil moisture content with a negative correlation. Using foam and bentonite together for conditioning can have a better result than using foam or bentonite alone. The concentration is proposed to be 14.3% for bentonite and 3% for foam while the injection rate is a range. There are many assembles which can meet the demand. For instance, the optimum injection rate is about 15% to 20% for foam and 12% for bentonite, or 30% to 35% for foam and 6% for bentonite. Polymer is proposed under rich underwater environment. Besides, under normal circumstances, polymer also can be used for lowing bentonite concentration, which can save bentonite consumption to reduce project cost.
Soil conditioning is used to improve the plastic flow capacity of earth pressure balance(EPB) in sandy cobble strata. Conditioning tests were conducted for sandy cobble strata in Chengdu by using foam, bentonite, and polymer, including the slump test, the stirring test as well as the viscosity test. The results show that sodium bentonite has a better bulking capacity than Ca-bentonite and is not layered, which is more suitable for soil conditioning. The reasonable ratio for bentonite alone is to have a concentration of 14.3% and an injection rate of 20%. The foam injection rate is influenced by soil moisture content with a negative correlation. Using foam and bentonite together for conditioning can have a better result than using foam or bentonite alone. The concentration is proposed to be 14.3% for bentonite and 3% for foam while the injection rate is a range. There are many assembles which can meet the demand. For instance, the optimum injection rate is about 15% to 20% for foam and 12% for bentonite, or 30% to 35% for foam and 6% for bentonite. Polymer is proposed under rich underwater environment. Besides, under normal circumstances, polymer also can be used for lowing bentonite concentration, which can save bentonite consumption to reduce project cost.
引文
[1] SOTIRIS P.Properties of foam/sand mixtures for tunneling applications [D].Oxford:St Hugh’s College,2001:84-85.
[2] BEZUIJEN A,SCHAMINEE P E L,KLEINJAN J A.Additive testing for earth pressure balance shields[C]//Twelfth European Conference on Soil Mechanics and Geotechnical Engineering.Balkema:[s.n.],1999:1991-1996.
[3] JANCSECZ S,KRAUSE R,LANGMAACK L.Advantages of soil conditioning in shield tunnelling:experiences of LRTS Izmir [C]//Proceedings ITA-AITES World Tunnel Congress.Oslo:ITA-AITES World Tunnel Congress,1999:865-875.
[4] 唐益群,宋永辉,周念清,等.土压平衡盾构在砂性土中施工问题的试验研究[J].岩石力学与工程学报,2005,24(1):52.TANG Yiqun,SONG Yonghui,ZHOU Nianqing,et al.Experimental research on troubles of EPB shield construction in sandy soil [J].Chinese Journal of Rock Mechanics and Engineering,2005,24(1):52.
[5] 许恺,季昌,周顺华.砂性土层盾构掘进面前土体改良现场试验[J].土木工程学报,2012,45(9):147.XU Kai,JI Chang,ZHOU Shunhua.Soil conditioning field test before heading face of EPB shield in sandy soil [J].China Civil Engineering Journal,2012,45(9):147.
[6] 张旭东.土压平衡盾构穿越富水砂层施工技术探讨[J].岩土工程学报,2009,31(9):1445.ZHANG Xudong.Construction technology of earth pressure balance shield in watery sandy stratum [J].Chinese Journal of Geotechnical Engineering,2009,31(9):1445.
[7] 许有俊,文中坤,闫履顺,等.多刀盘土压平衡矩形顶管隧道土体改良试验研究[J].岩土工程学报,2016,38(2):288.XU Youjun,WEN Zhongkun,YAN Lüshun,et al.Experimental study on soil improvement during construction of EPB rectangular pipe jacking with multi-cutter [J].Chinese Journal of Geotechnical Engineering,2016,38(2):288.
[8] 邱龑,杨新安,唐卓华,等.富水砂层土压平衡盾构施工渣土改良试验[J].同济大学学报(自然科学版),2015,43(11):1703.QIU Yan,YANG Xin’an,TANG Zhuohua,et al.Soil improvement for earth pressure balance shields construction in watered sandy stratum [J].Journal of Tongji University(Natural Science),2015,43(11):1703.
[9] 郭彩霞,孔恒,王梦恕.无水大粒径漂卵砾石地层土压平衡盾构施工渣土改良分析[J].土木工程学报,2015,48(增刊1):201.GUO Caixia,KONG Heng,WANG Mengshu.Study on muck improvement of EPB shield tunneling in waterless sandy-cobble-boulder stratum [J].China Civil Engineering Journal,2015,48(S1):201.
[10] 江华,张晋勋,苏艺,等.砂卵石地层土压平衡盾构隧道施工土体改良试验研究[J].中国铁道科学,2013,34(4):40.JIANG Hua,ZHANG Jinxun,SU Yi,et al.Study on soil conditioning experiments during earth pressure balance shield tunneling in sandy gravel strata [J].China Railway Science,2013,34(4):40.
[11] 姜厚停,龚秋明,杜修力.卵石地层土压平衡盾构施工土体改良试验研究[J].岩土工程学报,2013,35(2):284.JIANG Houting,GONG Qiuming,DU Xiuli.Experimental study on soil conditioning in cobble layer by use of earth pressure balanced machine [J].Chinese Journal of Geotechnical Engineering,2013,35(2):284.
[12] 贺少辉,张淑朝,李承辉,等.砂卵石地层高水压条件下盾构掘进喷涌控制研究[J].岩土工程学报,2017,39(9):1583.HE Shaohui,ZHANG Shuchao,LI Chenghui,et al.Blowout control during EPB shield tunnelling in sandy pebble stratum with high groundwater pressure [J].Chinese Journal of Geotechnical Engineering,2017,39(9):1583.
[2] BEZUIJEN A,SCHAMINEE P E L,KLEINJAN J A.Additive testing for earth pressure balance shields[C]//Twelfth European Conference on Soil Mechanics and Geotechnical Engineering.Balkema:[s.n.],1999:1991-1996.
[3] JANCSECZ S,KRAUSE R,LANGMAACK L.Advantages of soil conditioning in shield tunnelling:experiences of LRTS Izmir [C]//Proceedings ITA-AITES World Tunnel Congress.Oslo:ITA-AITES World Tunnel Congress,1999:865-875.
[4] 唐益群,宋永辉,周念清,等.土压平衡盾构在砂性土中施工问题的试验研究[J].岩石力学与工程学报,2005,24(1):52.TANG Yiqun,SONG Yonghui,ZHOU Nianqing,et al.Experimental research on troubles of EPB shield construction in sandy soil [J].Chinese Journal of Rock Mechanics and Engineering,2005,24(1):52.
[5] 许恺,季昌,周顺华.砂性土层盾构掘进面前土体改良现场试验[J].土木工程学报,2012,45(9):147.XU Kai,JI Chang,ZHOU Shunhua.Soil conditioning field test before heading face of EPB shield in sandy soil [J].China Civil Engineering Journal,2012,45(9):147.
[6] 张旭东.土压平衡盾构穿越富水砂层施工技术探讨[J].岩土工程学报,2009,31(9):1445.ZHANG Xudong.Construction technology of earth pressure balance shield in watery sandy stratum [J].Chinese Journal of Geotechnical Engineering,2009,31(9):1445.
[7] 许有俊,文中坤,闫履顺,等.多刀盘土压平衡矩形顶管隧道土体改良试验研究[J].岩土工程学报,2016,38(2):288.XU Youjun,WEN Zhongkun,YAN Lüshun,et al.Experimental study on soil improvement during construction of EPB rectangular pipe jacking with multi-cutter [J].Chinese Journal of Geotechnical Engineering,2016,38(2):288.
[8] 邱龑,杨新安,唐卓华,等.富水砂层土压平衡盾构施工渣土改良试验[J].同济大学学报(自然科学版),2015,43(11):1703.QIU Yan,YANG Xin’an,TANG Zhuohua,et al.Soil improvement for earth pressure balance shields construction in watered sandy stratum [J].Journal of Tongji University(Natural Science),2015,43(11):1703.
[9] 郭彩霞,孔恒,王梦恕.无水大粒径漂卵砾石地层土压平衡盾构施工渣土改良分析[J].土木工程学报,2015,48(增刊1):201.GUO Caixia,KONG Heng,WANG Mengshu.Study on muck improvement of EPB shield tunneling in waterless sandy-cobble-boulder stratum [J].China Civil Engineering Journal,2015,48(S1):201.
[10] 江华,张晋勋,苏艺,等.砂卵石地层土压平衡盾构隧道施工土体改良试验研究[J].中国铁道科学,2013,34(4):40.JIANG Hua,ZHANG Jinxun,SU Yi,et al.Study on soil conditioning experiments during earth pressure balance shield tunneling in sandy gravel strata [J].China Railway Science,2013,34(4):40.
[11] 姜厚停,龚秋明,杜修力.卵石地层土压平衡盾构施工土体改良试验研究[J].岩土工程学报,2013,35(2):284.JIANG Houting,GONG Qiuming,DU Xiuli.Experimental study on soil conditioning in cobble layer by use of earth pressure balanced machine [J].Chinese Journal of Geotechnical Engineering,2013,35(2):284.
[12] 贺少辉,张淑朝,李承辉,等.砂卵石地层高水压条件下盾构掘进喷涌控制研究[J].岩土工程学报,2017,39(9):1583.HE Shaohui,ZHANG Shuchao,LI Chenghui,et al.Blowout control during EPB shield tunnelling in sandy pebble stratum with high groundwater pressure [J].Chinese Journal of Geotechnical Engineering,2017,39(9):1583.