Monitoring of Landslide Deformation in the Upper Reaches of China's Yellow River and Simulation of Full-Scale Disaster Surge-Induced Dam Breaches: A Case Study of Lijiaxia

ABSTRACT
The canyon section of the upper Yellow River is characterized by complex geological conditions and frequent landslide hazards, which pose a cascading disaster threat to the cascade hydropower systems. This study takes the Likan Highway–Lijiaxia landslide as a typical case and systematically evaluates the risk of the landslide–surge–dam failure disaster chain through integrated multi-source remote sensing, time-series InSAR monitoring, material composition analysis, and multi-process coupled numerical simulation. Using more than 80 Sentinel-1A SAR images acquired between 2018 and 2023, a millimeter-scale deformation field of the landslide was derived using the SBAS-InSAR technique, revealing a maximum annual deformation rate of 24 mm/a at the landslide front and a cumulative deformation of 133 mm. Field investigations and laboratory tests identified that the landslide body consists mainly of Neogene mudstone breccia, with the slip zone rich in illite (content 18%–25%) and exhibiting low residual strength.

For disaster chain simulation, a fully coupled numerical model of “landslide motion – surge generation – dam response” was developed:

• The landslide motion module employs the Material Point Method (MPM) to simulate the dynamic process from slope failure to water impact, incorporating strain softening of the slip surface and debris fluidization.

• The surge generation and propagation module is based on the Volume of Fluid (VOF) method solving the 3D Navier–Stokes equations, implemented in FLOW-3D to simulate transient flow and capture air–water–solid interactions.

• The dam response module uses Fluid–Structure Interaction (FSI) to dynamically transfer hydrodynamic loads to a finite element dam model (ABAQUS), considering a concrete damaged plasticity constitutive model and nonlinear foundation contact.

Five sliding scenarios were simulated (volume: 1–10 million m³, velocity: 5–20 m/s). Under the extreme scenario (10 million m³, 20 m/s), the initial surge height reached 35–45 m, attenuating to 15–20 m at the dam face, with peak impact pressure of 250–320 kPa. Dynamic time-history analysis indicated that local areas of the dam may experience tensile damage (maximum damage factor D_max = 0.15–0.22), though the overall stability safety factor remains above the code limit (F_s > 1.05). Sensitivity analysis showed that sliding velocity has approximately 1.8 times greater influence on surge height than landslide volume.

The proposed framework of “integrated space–air–ground monitoring and multi-process coupled simulation” provides a quantitative risk assessment tool for the entire disaster chain—from landslide detection to dam safety evaluation—and offers critical technical support for disaster prevention decisions in hydropower projects along the upper Yellow River.

KEYWORDS: Upper Yellow River; InSAR; landslide material composition; surge simulation; fluid–structure interaction; disaster chain

                               Study Area Location Map

              Geological Map of the Study Area