Figure 20Dam break patterns for the landslide dam: (a) actual situation and (b) experimental result.As shown in Figure 20(b), the actual dam selleck Imatinib Mesylate break is similar to the experimental dam break. After the dam breaks, tiny particles are transported away and the larger particles collapse. Because the channel slope is low, a large number of particles are trapped downstream close to the dam, with the larger particles left on the surface. The experiment and the field site observations are generally consistent, which agree with the general models of dam breaks. 5. ConclusionsDam breaks of landslide dams are disastrous to property and life downstream. Fully understanding the process of dam break is very important for reducing damage and formulating effective disaster prevention and mitigation measures.

This study uses the Jiadanwan landslide dam as a classic example of a modern landslide dam. Laboratory tests are used to study the dam break mechanisms of landslide dams. Four factors considered in these experiments that impact the dam break of a landslide dam are the following: (a) water flow conditions, (b) the effects of boulders on the top of a landslide dam, (c) dam size, and (d) discharge channel characteristics. Experimental results show that partial dam break occurs downstream of the landslide dam when the water flow is 0.1L/s and 0.2L/s, and full dam break of the landslide dam occurs when the water flow is 2.0L/s. Boulders at the top of a dam can minimise erosion of a landslide dam when the water flow is under a certain value.

If the dam is thinner, the stability and erosion resistibility is relatively poor, and dam break occurs easily under normal water flow conditions. The stability of a landslide dam with a discharge channel can be decreased and result in a full dam break. Experiments are an effective method to investigate the mechanisms of dam break of landslide dams. However, experiments are limited by model size. The scaling relationships of models and natural landslide dams can be complicated and result in significant differences between experiments and field observations.AcknowledgmentsThe authors gratefully acknowledge the support of the National Natural Science Foundation of China (41102194, 41030742), the Opening Fund of State Key Laboratory of Geohazard Prevention and Geoenvironment Protection (Chengdu University of Technology) (SKLGP2013K015), and the China Postdoctoral Science Foundation Funded Project (2012T50785).

Polychaetes display an extraordinary diversity of reproductive traits [1], probably due to their high plasticity and adaptability to different habitats [2�C7]. Polychaetes, located in unpredictable environments, have been deeply studied to understand the characteristics of their life cycle. Fauchald [8] has divided Drug_discovery polychaetes into three general reproductive life styles.