拉线式深层沉降监测装置的研制

Development of Draw-wire Type Displacement Instrument for Monitoring Subsurface Settlement

在湿陷性黄土场地试坑浸水试验的深层沉降监测中,传统的深标点法仅能单孔单点测量、电磁式沉降仪法存在测量误差大等不足。为此,研制了一种拉线式深层沉降监测新装置。该新装置的基本原理是在监测点处开挖竖直探井,沿探井圆周均匀设置多个深层测点,将锚固头安装至测点处的探井侧壁上,当测点处土层发生湿陷变形时,首先由锚固头将变形传递给测绳,然后再由测绳传递至立柱上的滑块,最后通过量测立柱上的固定支座与滑块之间的相对位移,结合几何水准测量结果,得到各测点的深层沉降量。新装置与传统深标点法的现场对比试验结果表明,新装置具有原理清晰、结构简单、量程可调、精度高等优点,既满足了单孔多点测量需求,又提高了测量结果可靠性。最后对该新装置尚存在的问题进行了探讨,并提出了改进建议。

In the subsurface settlement monitoring of field soaking test in collapsible loess regions, the traditional subsurface settlement monitoring pole can only measure the settlement of a single position in a hole, and the electromagnetic settlement gauge has some disadvantages, such as large measurement error and so on. Therefore, a new type of draw-wire type displacement instrument for monitoring subsurface settlement is developed. The basic principle of the new instrument is to excavate a vertical exploration well at the monitoring site. Subsurface settlement monitoring positions are evenly set along the circumference of the exploration well, and the anchor head is installed on the side wall of the exploration well at the measuring position. When the soil layer is collapsible, the deformation is first transmitted to the measuring wire by the anchor head, and then to the slide block on the column by the measuring rope. Finally, the subsurface settlement of each measuring position is obtained by measuring the relative displacement between the fixed support and the sliding block on the column, and combined with the geometric leveling results. Based on field tests for comparing the new instrument and the traditional subsurface settlement monitoring pole, it is concluded that the new instrument with the advantages of working principle is clear, and structure is simple, and measurement range is adjustable, and precision is high, which not only meets the needs of multi-position measurement in a single hole, but also improves the reliability of measurements. Finally, the existing problems of the new instrument are discussed and suggestions for improvement are put forward.