针对现有沉井施工过程中侧摩阻力测试方法要求高、难度大的问题，自主设计研发一套侧摩阻力直接测试装置，并提出输出电压与侧摩阻力的理论转化公式。通过有限元软件对不同传感器平行梁尺寸下梁端应变和最大应力、不同密封材料下装置的应变损失进行分析，指导传感器平行梁尺寸及密封材料的选择，并利用大型直剪仪对装置进行精准标定，最后在哈尔滨某沉井工程中进行现场应用。研究结果表明： 1）平行梁的厚度越小、长度越大，弹性元件在荷载作用下微应变越大，但同时最大应力会增大； 2）传感器内填充密封材料后，会存在一定应变损失，采用硅酮结构胶对装置进行密封应变损失最小； 3）不同法向应力加载条件下侧摩阻力监测装置标定曲线的一致性较好，线性拟合系数均大于0.99，装置稳定性好。现场应用结果表明，通过侧摩阻力监测装置获取的沉井侧摩阻力与侧壁土压力的分布规律基本一致，且装置易于安装，可靠性好。
Existing monitoring methods for lateral friction
resistance in open caisson construction have inherent limitations, such as high
requirements and difficulties. Consequently, a novel direct test device for lateral
friction resistance is independently designed and developed. The finite element
software is used to analyze the strain and maximum stress at the beam end under
various sensor parallel beam sizes and the strain loss of the device under
different sealing fillers. This analysis guides the selection of sensor size
and sealing fillers. Additionally, a large direct shear apparatus is employed
to calibrate the device accurately. Subsequently, the proposed device was
applied in a caisson project in Harbin, China. This research produces the
following results: (1) Decreasing the thickness and increasing the length of
the parallel beam results in greater microstrain of the elastic element under
load, although the maximum stress concurrently increases. (2) Introducing a
sealing material into the sensor leads to a particular strain loss, with 10%
sealing strain loss observed for the device with a silicone structure. (3)
Calibration curves under different normal stresses exhibit good consistency,
with linear fitting coefficients exceeding 0.99, indicating device stability.
Field application results reveal that the distribution patterns of lateral
friction resistance and lateral earth pressure obtained from the lateral
friction resistance monitoring device are closely aligned. The device is easy
to install, and its results are reliable.
