非对称荷载作用下土体劈裂注浆压力分析

为研究在非对称荷载作用下土体劈裂注浆压力，基于扩孔理论和统一强度准则并考虑非对称荷载的作用，建立基于扩孔理论的劈裂注浆启劈压力分析模型，推导出浆泡周围塑性区土体的应力场、位移场、塑性区半径以及启劈注浆压力的理论解答，并以工程算例进行论证。结果表明，考虑对称荷载作用下的启劈注浆启劈压力较考虑非对称荷载作用下的值要大，对称荷载作用下的分析方法低估了塑性区半径；无论是柱形劈裂还是球形劈裂，当 1时，启劈压力会随着 的增大而增大，塑性半径会随着 的增大而明显减小；当 1时，启劈压力会随着 的增大而减小，而塑性半径的变化是有限的。预先了解土体的初始应力条件对正确的确定劈裂注浆启劈压力至关重要，可为劈裂注浆的设计和施工会提供更加完善的理论依据。

Analysis of soil fracturing grouting pressure under asymmetric loads

In order to study the soil fracturing grouting pressure under asymmetric loads, based on the cavity expansion theory and unified strength theory and considering the influence of the asymmetric loads, the analytical solutions of stress fields and displacement fields in the plastic regions surrounding slurry bubble, as well as the radius of plastic region and limit expansion pressure are deduced. The solutions are validated through the engineering example. The results show that grouting pressure considering the symmetrical load is larger than that considering the asymmetric loads, which indicates that the radius of plastic region are underestimated in the analysis of grouting under the symmetrical load. For the cylindrical cavity expansion and the spherical cavity expansion, where K0 is less than 1, the starting fracturing pressure increases with the increment of K0; while the radius of plastic region significantly decreases with the increment of K0. Where K0 is greater than 1, the starting fracturing pressure decreases with the increment of K0, but the change of radius of plastic region is limited. Therefore it is important to estimate the initial stress conditions of the soil previously before the critical fracturing pressure. The results will improve theoretical basis for design and construction of fracturing grouting.