新型光纖光柵高解析監測技術於污染場址 水文地質參數異質場調查

To access and predict the movement of the plume and remediation agent in the aquifers, it is essential to understand the detailed hydrogeological parameters fields. However, the unrealistic homogenous assumptions in traditional pumping and slug tests hardly convey these three-dimensional parameter fields accurately. To characterize the aquifer heterogeneity of contaminated site (hydraulic conductivity K and specific storage Ss), a new technology is investigated on the basis of Hydraulic Tomography (HT). The newly developed technology consists of two parts: (1) A multilevel observation well consists of rubber packers and fiber Bragg grating (FBG) piezometer and thermometer. (2) Integrating singular value decomposition (SVD) into successive linear estimator (SLE). This method reduces the dimension of covariance matrix of the parameters that need to be estimated. Thus, the SLE's computational loading could be reduced effectively. The proposed method is verified by conducting an HT field test through agent injection during a site remediation event. Besides the FBG experiments, a cross-hole electrical resistivity survey (CHERT) was conducted to understand the sediment structure of the study site, and the CHERT profiles are used to validate the estimated K fields. The results show that the obtained resistivity image profiles are consistent with the estimated K fields. Finally, we utilized the estimated K and Ss fields to simulate the movement of remediation agent. Once the spatial distribution of the remediation agent is obtained, the area where the agent is unable to reach could be observed, we can thus adjust the remediation agent injection strategy to guarantee the agent contact the plume.