高压旋喷桩对现役高速公路的加固效果分析

Performance evaluatiohn of operating expressway reinforced with high pressure jet-grouting pile

为解决现役高速公路长期变形问题,以连盐高速公路灌云段为对象,采用高压旋喷桩进行路基加固处理。针对高压旋喷桩加固效果,建立ABAQUS有限元三维模型,并采用现场实测数据对模型的合理性进行验证。分析高压旋喷桩桩体弹性模量、桩长、桩直径、桩间距、面积置换率以及公路运营时间对加固效果的影响。研究结果表明:采用高压旋喷桩进行处理,其工后沉降为2~3cm,加固效果明显;桩体弹性模量、桩径、桩间距和桩长、面积置换率均会影响加固效果,但桩体弹性模量影响较小;在面积置换率为8.7%情况下,桩径比桩间距对加固效果的影响大,桩长对加固效果的影响最大;在相同加固桩体处理下,处理时间越早,其运营期总沉降越小,但加固后固结沉降呈现增大趋势。

To solve the problem of the long-term settlement of the operating expressway, part of the operating Lian-Yan express-way embankment, namely the Guan Yun section, was reinforced with the high pressure jet grouting pile technique. A three-di-mensional FEM model was developed by using ABAQUS software in order to investigate the mechanism of the reinforced embank-ment. The model was verified by comparing the field test data with the FEM simulation results. Factors, including elastic modu-lus of pile, length and diameter of pile, pile spacing, the ratio of the area replacement and operating time, were selected to cap-ture the influence of these factors on the reinforcement. The results showed that the post-construction settlement varied from 2 to 3 cm when the embankment was reinforced by the high pressure jet grouting pile technique. This indicated that the use of high pressure jet grouting pile technique was an effective method in controlling the differential settlement. In addition, it was found that factors of length and diameter of piles and pile spacing all have significant influence on the reinforcing effect, while it was not sensitive to the elastic modulus of pile. Furthermore, when the ratio of the area replacement was 8. 7%, the reinforcement effect was more sensitive to the diameter of pile than the pile spacing. The factor of pile length was the most important factor affecting the embankment reinforcement. Under the same parameters of the pile, the shorter operating time of the expressway lead to the less operating consolidation settlement, while the consolidation settlement showed an increasing trend after reinforcement.