囊袋式注浆对盾构下穿高速铁路路基沉降的控制效果

Control Effect of Capsuled Grouting on Settlement While Shield Tunneling Underpass High Speed Railway Subgrade

高铁路基的沉降变形是影响运营安全的重要因素,盾构下穿既有高铁线路施工可诱发高铁路基沉降变形。为有效控制高铁路基沉降,基于数值模拟探究了囊袋式注浆作为高铁路基沉降主动控制措施的有效性。结果表明:注浆囊袋对其周围土体的影响具有局部性,地层等效塑性应变随注浆体埋深的增加而增大,且塑性区厚度通常小于注浆囊袋膨胀厚度的3.0倍。囊袋的埋设深度和膨胀直径对路基抬升整治范围有影响,囊袋埋设越浅其膨胀后对路基抬升的影响效果越明显,且路基表层的隆起变形曲线符合高斯方程。提出了盾构下穿高铁路基时囊袋式注浆控制措施下路基沉降预测模型,可指导盾构下穿高铁路基的沉降控制。

The settlement deformation of high speed railway subgrade is an important factor affecting the operation safety.The construction of shield tunneling underpass existing high speed railway line can induce the settlement deformation of high speed railway subgrade.The effectiveness of bag grouting as an active control measure for high speed railway subgrade settlement was explored based on numerical simulation to control the settlement of high speed railway subgrade effectively.The results show that,the influence of the bag grouting body on the surrounding soil is local,and the equivalent plastic strain of the stratum increases with the increase of the buried depth of the grouting body,and the thickness of the plastic zone is usually less than 3.0 times of the expansion thickness of the grouting bag.The shallower the buried bag is,the more obvious the effect of expansion on the subgrade is uplift,and the uplift deformation curve偶of subgrade surface conforms to the Gauss equation.The prediction model of subgrade settlement under the control measures of capsular grouting is put forward,which can guide the settlement control of shield tunneling under high speed railway subgrade.