Geological and hydrogeological conditions in karst areas are complicated from the viewpoint of engineering. The construction of underground structures in these areas is often disturbed by the gushing of karst water, which may delay the construction schedule, result in economic losses, and even cause heavy casualties. In this paper, an innovative method of multichannel transient Rayleigh wave detecting is proposed by introducing the concept of arrival time difference phase between channels (TDP). Overcoming the restriction of the space-sampling law, the proposed method can extract the phase velocities of different frequency components from only two channels of transient Rayleigh wave recorded on two adjacent detecting points. This feature greatly improves the work efficiency and lateral resolution of transient Rayleigh wave detecting. The improved multichannel transient Rayleigh wave detecting method is applied to the detection of karst caves and fractures in rock mass of the foundation pit of Yan’an Road Station of Guiyang Metro. The imaging of the detecting results clearly reveals the distribution of karst water inflow channels, which provided significant guidance for water plugging and enabled good control over karst water gushing in the foundation pit.

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Background: Most degenerative lumbar spinal stenosis (DLSS) patients primitively received the conservative treatment to control symptoms. In order to develop an optimal surgical treatment strategy, it is very significant to understand how the degenerative lumbar spondylolisthesis (DS) affects the effect of decompression in the DLSS. Thus, the aim of this current study was to explore whether the concomitant DS would affect the effect of decompression alone in the patients with DLSS. Methods: The current study was carried out at our hospital and it was approved through our institutional review committee of General Hospital of Ningxia Medical University. During the period from January 2015 to December 2017, in our study, we identified consecutive patients who received the minimally invasive laminectomy to treat the DLSS. The inclusion criterion included radicular leg pain or neurogenic claudication with the neurological symptoms associated with DLSS syndrome, magnetic resonance imaging of the lumbar spine reveals at least 1 level of serious stenosis, the conservative treatment failed for at least 3 months, and patients agreed to provide the postoperative details. The major outcomes of this present research was Oswestry Disability Index. Secondary outcomes of this current study involved visual analog score, short form-36, surgical revision rate as well as complications. Results: We assumed that previous DS possessed a negative effect on the postoperative results of the DLSS patients. Trial registration: researchregistry5943.

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