不同材质腰梁对锚索预应力损失的影响研究

为研究不同材质腰梁对锚索预应力损失的影响规律，依托青岛海天中心桩锚支护深基坑工程，结合现场实测和ABAQUS有限元数值模拟，阐明了3种不同材质腰梁作用下锚索预应力变化规律，并将模拟结果与实测结果进行对比分析。结果表明：模拟结果与实测结果变化规律基本一致；锚索预应力随时间的变化趋势较平缓，分为快速下降、稳定变化和基本稳定3个阶段；加载过程中，锚索应力由自由段向锚固段传递，逐渐传递到支护桩及桩后土体；影响锚索预应力损失的主要因素为突然卸荷引起的锚索回缩、土体蠕变和岩土体流变变形。最后对比分析了玻璃纤维增强聚合物(glass fiber reinforced polymer, GFRP)腰梁、混凝土腰梁和钢腰梁作用下锚索预应力损失规律，整体损失率分别为6.89%、14.74%、16.84%,表明GFRP腰梁具有控制锚索预应力损失的绝对优势，研究成果可为类似深基坑工程的设计提供参考和借鉴。

Study on the influence of different material waist beams on anchor cable prestress loss

In order to study the influence of different materials on the prestress loss law of anchor cable, based on the deep foundation pit project of Pile-anchor support in Qingdao Haitian Center, combined with the field measurement and ABAQUS finite element numerical simulation, the variation law of anchor cable prestress under the action of three different materials of waist beam was explained, and the simulation results were compared with the measured results. The results show that the simulated results are basically consistent with the measured ones. The prestress of anchor cable changes gently with time, which can be divided into three stages: rapid decline, stable change and basic stability. During the loading process, the anchor cable stress is transferred from the free section to the anchorage section, and gradually to the retaining pile and the soil behind the pile. The main factors affecting prestress loss of anchor cable are cable retraction, creep of soil mass and rheological deformation of rock mass caused by sudden unloading. Finally, the prestress loss rule of anchor cable under the action of GFRP waist beam, concrete waist beam and steel waist beam is compared and analyzed, and the overall loss rate is 6.89%, 14.74% and 16.84%, respectively. It shows that GFRP waist beam has absolute advantage in controlling the prestress loss of anchor cable. The research results can provide reference for the design of similar deep foundation pit engineering.