Kong Jiming

Dynamical mechanisms of effects of landslides on long distance oil and gas pipelines

According to the investigations on the oil and gas pipelines such as the Lan-Cheng-Chong pipeline and the Southwest pipeline, there are two ways of laying pipeline: pipelines paralleling (approximately) to the main slide direction and pipelines perpendicular (approximately) to the main slide direction. If earth-retaining walls have been built for pipelines paralleling to the main slide direction, they will prevent the lands from sliding: On the contrary, without earth-retaining walls, the sharp broken rocks in the backfilling soil will scratch the safeguard of the pipeline when the landslides take place. Pipelines perpendicular to the main slide direction can be classified into four types according to the relative positions between pipelines and landslides: Pipelines over the slide planes, pipelines inside the fracture strips of slide planes, pipelines below the slide planes and pipelines behind the backsides of landslides. The different dynamical mechanisms of the process in which landslide acts against pipelines are analyzed based on whether the pipelines are equipped with fixed frusta, because the sliding resistance depends on whether and how many fixed frusta are equipped and the distance between frusta.

Deformation and development tendency of Shiliushubao landslide by numerical modeling

On the basis of analysing basic features of Shiliushubao landslide, the landslides deformation and development tendency are quantitatively studied by using FLAC3D program. The results accord with monitoring results. The results are indicated that reservoir impounding accelerates the landslides deformation, and the variation of reservoir water level is key factor of affecting the deformation; The landslide has the characters of pull-behind movement according to the displacement of the landslide body gradually reducing from leading edge to trailing edge; Excavating and deloading slow down the landslides deformation in the certain degree. On the basis, the deformation developmental tendency of Shiliushubao landslide is predicted by the established simulating model.

Occurrence conditions and process analysis on fluidization of valley type landslide: Example of the fluidization of landslide in Qiongshan Ravine, Danba

A big debris flow which was arosed by landslide occurrence at night on July 11, 2003 in Qiongshan Ravine, Danba, Sichuan Province. According to the research, debris flow in Qiongshan Ravine is arosed by the fluidization of landslide. It had been rained about 70 days before debris flow occurred. That made the sediments in the gully to near to saturated or saturated in water. Being affect by the steep geography, the sediments occurrence peristalsis to transform, parts of soil bodies start disintegrate. All the sediments become transforming with water inleakaging to sediments, and than foreside slope flow to gully quickly after becoming fluidization. And the sediments come into being the debris flow with the water of the gully joining.

The excavation effect of complex rock high slope

In the course of complex rock slope excavation, with the rescission of lateral stress constraint, the rock mass will produce unloading rebound deformation to the free face. With this course, the primary equilibrium stress state in slope mass is broken, and secondary stress adjustment occurs, which will adapt to the deformation state of continual development until new balance. The result is that the distribution areas of secondary stress field form in the slope mass at a certain depth. Theoretically, when the slope deformation finished, the secondary adjustment is also over. For convenience of study, the primary equilibrium stress state before excavation is called the first balance state of ground stress. And the stress field of secondary adjustment named the second balance state after excavation. In this paper, a kind of slope is chosen to study by using numerical simulation. The ground stress release rules of highway cutting slope after excavation from first balance state to the second are researched. And the partition of secondary stress is also studied. The ground stress consideration in the slope stability analysis after excavation is discussed.

Research the Excavation Angle Affect on Seismic Dynamic Response of Slope

Based on the concentrated deformation and destruction characteristics of excavation damage slopes in Wenchuan earthquake，as granite the media of excavation damage slope for the finite element model. In 45° slope as the natural slope，the excavation damage effect and seismic dynamic response of different excavation angle have been studied under the excavation high is certain condition, it’s include natural slopes, excavation angle 56°, 72° and 90°. Analysis shows that excavation damage not only themselves destroyed the stress balance of slopes, but also impact on the seismic dynamic response of slopes, and the seismic dynamic stress, displacement and acceleration increased with the increase of slope angle. It’s not conducive to the stability of slope and the results coincides with the investigation conclusion that Wenchuan earthquake mountain disaster outbreak in the terrain mutation site. And the analysis also shows that slow excavation angle is an important measure to improve the seismic performance of the slope.

Criterions and Measures of Route Selection of Shallowly Embedded Long-distance oil and Gas Pipeline in Mountain Areas

According to the engineering investigation of long-distance oil and gas pipelines, the criterions and measures of route selection are drawn as follows: the flat landform is the first choice in route alignment. The foot of mountain is the first choice when the route passes by the valley. The route should pass by but the shady and deposited slope and not in sunny and erosive slope as possible as it can. The pipeline should be vertical to contour climbing and descending the mountain except steep slope. Tunnel can be used in crossing foothill. Perpendicularly traversing the river is better than beveling; the worst choice is to put the pipeline along the river. Bypass is the best choice in karsts area. The order of route selection should be pre-choosing, investigation, optimization and adjustment.