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Based on the unit life and death technology, the dynamic evolution process of soil loss is considered, and a pipe-soil nonlinear coupling model of buried pipelines passing through the collapse area is constructed. The analysis shows that after the third layer of soil is lost, the existence of the “pipe-soil separation” phenomenon can be confirmed, which then supplements the assumption that “pipe-soil is always in contact” in the elastic foundation beam theory. Calculation of settlement deformation of buried pipelines It needs to be divided into two stages: cooperative deformation and non-cooperative deformation. Taking the settlement prediction of buried pipelines as the goal, the particle swarm algorithm (PSO) was used to optimize the number of neurons, Dropout, and Batch-size in the long short-term memory network (LSTM) structure. The optimization results were 60, 0.001, and 100, respectively. The PSO-LSTM model proposed in this article can accurately describe the dynamic evolution process of buried pipelines and has better prediction accuracy than the modified Gaussian curve method and LSTM neural network model. The use of this model can provide a reference for safety risk management, disaster early warning, and intelligent monitoring when buried pipelines suffer from soil collapse disasters.

Objective To investigate the effects of dexmedetomidine (Dex) on osteoporosis (OP) rats and possible mechanisms. Methods The rats were divided into sham operation group, osteoporosis model group (OP, replicating the OP rat model with bilateral ovariectomies), Dex-L, M, and H (Dex low, medium, and high dose treatments) groups and Dex-H+XAV-939 group (Wnt/β-catenin pathway inhibitor). Micro-CT was applied to measure bone mineral density (BMD) and bone microstructure of rat femurs. The three-point bending experiment was applied to analyze the biomechanics of the femur (maximum load, fracture deflection, elastic modulus). HE staining was applied to observe pathological changes in the femur of rats. ELISA method was applied to evaluate bone metabolism indicators such as alkaline phosphatase(ALP), typeⅠ procollagen amino-terminal peptide (PINP) and typeⅠcollagen cross-linked C-telopeptide(CTX-Ⅰ). The expression of Runx2 and Wnt3a was examined by Immunohistochemistry. Western blot was applied to detect the protein expression of Runx2 and Wnt3a/β-catenin pathway in femoral tissue. Results Compared to the Sham group, the bone volume and number of trabeculae in OP group were obviously reduced, the maximum load, fracture deflection, elastic modulus, BMD, Tb.Th, Tb.N, BV/TV, ALP, PINP, Runx2, Wnt3a, β-catenin expression decreased, CTX-Ⅰ increased (P＜0.05). Compared to the OP group, the bone trabecular structure in the Dex-L, M, and H groups was restored, the maximum load, fracture deflection, elastic modulus, BMD, Tb.Th, Tb.N, BV/TV, ALP, PINP, Runx2, Wnt3a, β-catenin expression all increased but CTX-Ⅰ decreased (P＜0.05). Compared to the Dex-H group, the bone trabecular injury in the Dex-H+XAV-939 group showed a more severe damage. The maximum load, fracture deflection, elastic modulus, BMD, Tb.Th, Tb.N, BV/TV, ALP, PINP, Runx2, Wnt3a, β-catenin expression decreased while CTX-Ⅰ increased (P＜0.05). Conclusions Dex may antagonize OP effects by improving bone density, biomechanical properties and microstructure. The underlying mechanism might be related to the activation of the Wnt/β-catenin signaling pathway.