The Ancient City in Lijiang of southwestern China was endowed as World Cultural Heritage by UNESCO, and the karst springs located in Black Dragon Pool are its main water source. However, the springs have dried up several times in recent years, which caused serious damages to the landscape as well as the city water supply. Triggered by the dried-up event in Black Dragon Pool, a long-distance artificial tracer test up to 17 km was employed to investigate the karst conduit network distributing in the study area. Based on the tracer concentration breakthrough curves (BTCs), the hydraulic connection from the same injection point (located in a giant depression named the Jiuzi Sea) to the springs on both sides of the topography watershed was proven, and the conduit structure was discussed. According to the characteristics of BTCs and considering the low tracer concentration and tracer recovery, a conceptual structure of leaky reservoir with threshold effect above a certain groundwater level was established to interpret why the springs in Black Dragon Pool dried up several times in history, but those in the Ancient City never did. Furthermore, a method of injecting surface water into the Jiuzi Sea to raise the groundwater level up to the height of Black Dragon Pool was proposed to restore the springs. Our study provides insights into the long-distance artificial tracer test, and opens a new avenue for groundwater resource recovery of this Ancient City.

No abstract

Historically, industries were in harbour areas of cities for easy access to transportation of resources.Today, transforming former industrial areas into living spaces has become attractive business. However, this transformation has often been challenged by high levels of soil contamination caused by the industrial use. Remediation measures are mandatory to ensure the public safety in the redeveloped areas.Detailed information about the contaminant type, distribution and transport mechanisms is required to address the contamination issues. This paper presents a workflow for investigations assisting decision making for construction work in redeveloped industrial areas. The workflow is applied to Horsens harbour (Denmark). In this area, renovation of the harbour walls introduces the risk of spreading of phenol contamination to planned construction areas. The study demonstrates how detailed information about the geology and hydrology at the site allows for scenario modelling of contaminant transport, guiding remediation efforts and aiding decision makers in developing the harbour area.

Historically, industries were in harbour areas of cities for easy access to transportation of resources. Today, transforming former industrial areas into living spaces has become attractive business. However, this transformation has often been challenged by high levels of soil contamination caused by the industrial use. Remediation measures are mandatory to ensure the public safety in the redeveloped areas. Detailed information about the contaminant type, distribution and transport mechanisms is required to address the contamination issues. This paper presents a workflow for investigations assisting decision making for construction work in redeveloped industrial areas. The workflow is applied to Horsens harbour (Denmark). In this area, renovation of the harbour walls introduces the risk of spreading of phenol contamination to planned construction areas. The study demonstrates how detailed information about the geology and hydrology at the site allows for scenario modelling of contaminant transport, guiding remediation efforts and aiding decision makers in developing the harbour area.

In order to obtain the accurate mechanical parameters of deep-buried coal goaf rock mass, the limitation of geological strength index (GSI) in concealed rock mass is analyzed. Based on the test result and analysis of the current normative standards, the classification indexes of rock mass structural are optimized based on discontinuity distance d and rock mass integrity index K v . The ratio of rock mass saturated strength to dry strength, η, is introduced, quantization formula of structural surface conditions is proposed, and the influence of groundwater and rock types is included in structural surface condition classification. The GSI system is improved to better suit all types of deep-buried and water-rich rock masses. Furthermore, the rock mass disturbance factor D’s quantitative formula is listed according to the Hoek–Brown (HB) criterion. Taking the goaf roof under railway as an example, the parameters of deep-buried rock mass are obtained based on the improved quantitative GSI system and HB criterion. This research provides a scientific reference for achieving geological parameters and engineering designing in goaf areas.