上覆压力对深厚覆盖层地基渗透及渗透稳定性的影响
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摘要
为了研究不同上覆压力对深厚覆盖层中管涌型土层的渗透及渗透稳定性影响,利用土体渗流—应力耦合装置,在施加不同上覆压力(0、0.3、0.5、0.7 MPa)的条件下,对缺级配砂砾石进行渗透破坏试验。结果表明,随着上覆压力的增大,土体在渗透破坏过程中,局部的渗透特性变化和渗流场分布均存在差异性,反映了细土颗粒被运移和填充孔隙的情况不同,从而影响了水力坡降在局部的分配情况;上覆压力的增大使得土体稳定渗流阶段和渗透破坏阶段的渗透性出现不同程度的减小,临界坡降和破坏坡降的变化与上覆压力之间存在相同形式的非均匀变化关系。
In order to study the impact of pressure on the permeability and permeable stability of piping soil layer in deep overburden,different overburden pressures(0 MPa,0.3 MPa,0.5 MPa,0.7 MPa)were applied using the soil seepage-stress coupling device.Under these conditions,seepage failure test was conducted on the lack of sand and gravel.It could be concluded that with the increase of overburden pressure,the local permeability characteristics and the seepage field distribution are different in the process of seepage failure,which reflects the different situations when fine-grained particles are transported and filled with pores.Thus,the local distribution of hydraulic gradients are different.The increase of overburden pressure makes the permeability of the stable seepage stage and the seepage failure stage of the soil appear different degrees of reduction.The study also shows that there is the form of non-uniform change correlation between the critical slopes and the overburden pressures.The same correlation has also been shown between the failure slopes and the overburden pressures.
In order to study the impact of pressure on the permeability and permeable stability of piping soil layer in deep overburden,different overburden pressures(0 MPa,0.3 MPa,0.5 MPa,0.7 MPa)were applied using the soil seepage-stress coupling device.Under these conditions,seepage failure test was conducted on the lack of sand and gravel.It could be concluded that with the increase of overburden pressure,the local permeability characteristics and the seepage field distribution are different in the process of seepage failure,which reflects the different situations when fine-grained particles are transported and filled with pores.Thus,the local distribution of hydraulic gradients are different.The increase of overburden pressure makes the permeability of the stable seepage stage and the seepage failure stage of the soil appear different degrees of reduction.The study also shows that there is the form of non-uniform change correlation between the critical slopes and the overburden pressures.The same correlation has also been shown between the failure slopes and the overburden pressures.
引文
[1]周建平,陈观福.深厚覆盖层坝基防渗处理及混凝土防渗墙设计[J].水力发电,2004,30(1):299-306.
[2]党林才,方光达.深厚覆盖层上建坝的主要技术问题[J].水力发电,2011,37(2):24-28.
[3]谢定松,蔡红,魏迎奇,等.覆盖层不良级配砂砾石料渗透稳定特性及影响因素探讨[J].水利学报,2014(S2):77-82.
[4]郭海庆,黄海燕,耿妍琼,等.箱形渗透试验仪中宽级配砂砾石渗流变形试验[J].水电能源科学,2012,30(10):54-57.
[5]SL237-1999,土工实验规程[S].北京:中国水利水电出版社,1999.
[2]党林才,方光达.深厚覆盖层上建坝的主要技术问题[J].水力发电,2011,37(2):24-28.
[3]谢定松,蔡红,魏迎奇,等.覆盖层不良级配砂砾石料渗透稳定特性及影响因素探讨[J].水利学报,2014(S2):77-82.
[4]郭海庆,黄海燕,耿妍琼,等.箱形渗透试验仪中宽级配砂砾石渗流变形试验[J].水电能源科学,2012,30(10):54-57.
[5]SL237-1999,土工实验规程[S].北京:中国水利水电出版社,1999.