冬季输水梯形渠道冻胀时水力因素对刚性衬砌层内力影响研究

对于冬季输水渠道,在其基土冻胀作用时边坡混凝土板力学模型得到实践工程检验的基础之上,又以实际工程渠道为参数,理论分析了在特定冻胀力作用类型及计算方法的条件下,其渠道坡角、水深和边坡混凝土板厚度的变化对边坡混凝土板内力的影响规律。结果表明:冬季输水渠道边坡板在冬季渠基土冻胀的过程中有沿坡面整体上移的趋势;在渠基土边坡整体稳定的前提条件下,增大渠道坡角、减小渠底宽、提高渠内水位可大大减少渠道冻胀作用时边坡板的内力,降低渠道冻胀破坏的机率;通过增加边坡板的厚度来提高渠道抗冻胀破坏能力是不可取的。该成果为季节冻土区冬季无冰盖输水渠道的抗冻胀破坏设计指出了设计新思路。根据设计流量,设计并调整渠道水力参数,尽可能使渠内水深提高,不仅降低渠道冻胀破坏的机率,还可以减少渠道用地面积和土方工程量。

Influence of hydraulic factors on the inner forces of rigid lining of trapezoidal water conveyance canal in winter during frost heaving

We tested in practical engineering the mechanical model of slope concrete slabs of winter water conveyance canals during the frost heaving of the bedsoil. Then we theoretically analyzed the influence of slope angle, water depth, and lining thickness on the inner forces of the rigid lining of the canal under the condition of a specific type of frost heaving force and calculation method. Results showed that the slope slab of the canal had a tendency to move upward along the slope during frost heaving of the bedsoil in winter. On the premise of overall stability of the slope, the innerforces and probability of canal damage due to frost heaving could both be greatly reduced by increasing slope angle, reducing canal bottom width, and rising water level. It is inadvisable to increase the slope slab thickness as a way to increase the frost heaving resistance capacity of the canal. The research findings can provide a new method for the anti-frost heaving design of water conveyance canals without ice cover in winter in seasonally frozen region. To design and adjust the hydraulic parameters of the canalso as to increase the water depth within the canal can reduce the probability of frost heaving damage to the canal, and can reduce the canal land area and earthwork volume.