面板堆石坝安全监测方法及应用

发布时间：2019-06-29 20:27

【摘要】：大坝安全监测是了解大坝运行状态和安全状况的有效手段和方法,是一个包括由获取各种环境、水文、结构、安全信息到经过识别、计算、判断等步骤,最终给出一个大坝安全程度的全过程。本文依据余姚市双溪口水库大坝安全监测项目,详细阐述面板堆石坝安全监测的监测布置、仪器选型、安装和观测方法以及观测结果数据分析,主要结论有：应变计在坝体填筑前监测数据稳定,随着大坝的填筑,由于坝体加载的影响,数据出现一定幅度的变化,水库蓄水后,随着库水位的上升,防渗墙各应变计呈现向压应力变化的趋势。蓄水前,固定式测斜仪由于坝体堆载的影响,呈向上游位移的状态,但位移量在允许范围内,位移无突变情况,随时间变化曲线比较平稳。蓄水后,随库水位的上升,各测点有向下游位移的趋势,最大位移量1.7cm,在正常范围内。渗压计埋设后,水库蓄水前,渗压计水位主要受降雨的影响,蓄水后,随着库水位的上升,除靠近防渗墙下游侧渗压计水位及位势有一定程度的增加,其余测点变幅较小,同时,渗流计算表明坝基不存在渗透稳定问题。各测压管水位主要受降雨影响,同时在库水位一样但时间相隔一年多的情况,相应的测压管水位无上升趋势。虽然防渗墙应变监测结果显示施工期拉应力超出有限元理论计算值,但渗压计及测压管监测资料分析表明防渗墙的防渗性能较好,未出现异常情况。水管式沉降仪各测点总的沉降量绝大部分发生在施工期,累积沉降量占坝高的百分数,最大值为0.94%。水库蓄水后,由于库水压力及坝体堆石蠕变的共同作用,部分测点沉降量增加,在正常范围内。目前所有测点沉降均处于稳定状态。引张式水平位移计在施工期靠近上游侧的测点向上游位移,下游侧测点向下游位移,蓄水位后,各测点呈向下游位移的趋势。三向测缝计受库水压力作用,与库水位有一定的相关性,在三个方向的变形均有所增加；双向测缝计的接缝受库水压力的作用,但与库水位的相关性很小；单向测缝计的接缝变化主要受外界气温影响。
[Abstract]:Dam safety monitoring is an effective means and method to understand the operation state and safety condition of the dam. It is a whole process from obtaining all kinds of environment, hydrological, structure, safety information to identification, calculation, judgment and so on, and finally gives a whole process of dam safety degree. According to the dam safety monitoring project of Shuangxikou Reservoir in Yuyao City, this paper expounds in detail the monitoring arrangement, instrument selection, installation and observation method and observation data analysis of face rockfill dam. The main conclusions are as follows: the monitoring data of strain gauge is stable before dam filling. With the filling of dam, due to the influence of dam loading, the data changes to a certain extent after reservoir impoundment. With the increase of reservoir water level, each strain gauge of impervious wall tends to change to compressive stress. Before water storage, the fixed inclinometer is in the state of upstream displacement due to the influence of the overloading of the dam body, but the displacement is within the allowable range, and the displacement is not abrupt, and the curve is stable with time. After water storage, with the increase of reservoir water level, each measuring point has a trend of downstream displacement, and the maximum displacement is 1.7 cm, which is in the normal range. After the seepage meter is buried, the water level of the seepage meter is mainly affected by rainfall before the reservoir impoundment. With the increase of the reservoir water level, the water level and potential of the seepage meter near the downstream side of the cutoff wall increase to a certain extent, but the variation of the other measuring points is small. At the same time, the seepage calculation shows that there is no seepage stability problem in the dam foundation. The water level of each pressure measuring pipe is mainly affected by rainfall. At the same time, when the reservoir water level is the same but the time interval is more than one year, the corresponding pressure pipe water level has no upward trend. Although the strain monitoring results of the impervious wall show that the tensile stress during the construction period exceeds the calculated value of the finite element theory, the analysis of the monitoring data of the seepage gauge and the pressure measuring tube shows that the impermeable performance of the impervious wall is good and there is no abnormal situation. Most of the total settlement of each measuring point of the water pipe settler occurred during the construction period, and the cumulative settlement accounted for the percentage of the dam height, and the maximum value was 0.94%. After reservoir impoundment, due to the joint action of reservoir water pressure and rockfill creep of dam body, the settlement of some measuring points increases, which is within the normal range. At present, the settlement of all measuring points is in a stable state. During the construction period, the displacement of the measuring point near the upstream side is upstream, and that of the downstream side is downstream. After the water level is stored, each measuring point shows the trend of downstream displacement. The three-way seam gauge is affected by the reservoir water pressure and has a certain correlation with the reservoir water level, and the deformation in all three directions is increased. The joint of the bidirectional seam meter is affected by the reservoir water pressure, but the correlation with the reservoir water level is very small, and the seam change of the one-way seam meter is mainly affected by the external air temperature.
【学位授予单位】：浙江大学
【学位级别】：硕士
【学位授予年份】：2014
【分类号】：TV698.1

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