卧龙幸福沟泥石流发育特征及发展趋势预测

发布时间：2018-06-22 06:23

本文选题：幸福沟 + 泥石流　；参考：《成都理工大学》2015年硕士论文

【摘要】：幸福沟为一典型沟谷型泥石流沟,地质历史时期曾发生过多期次规模巨大的泥石流。5.12地震后,沟域内产生了大量崩滑物源,并先后于2008年、2013年发生过两次大规模泥石流,其可能在近期再次发生大规模的泥石流,严重威胁到沟内大熊猫研究保护中心、大熊猫野生训养场及沟口耿达乡居民、S303省道的安全。因此,研究幸福沟泥石流的发育特征、运动特征及发展趋势,对指导泥石流防治工程设计,具有一定的实际意义。本论文在幸福沟地质地貌条件及泥石流发育特征系统调研基础上,研究幸福沟泥石流形成条件、古泥石流历史演化成因及震后泥石流活动性,并用CFX软件模拟“7.10”泥石流及P=1%暴雨频率下泥石流在沟道内的运动情况,在此基础上预测泥石流的发展趋势,提出泥石流的治理工程建议。取得了如下主要认识:(1)幸福沟是一条流域面积大,支沟发育的泥石流沟。“5.1”地震后,沟内新增大量的崩滑物源,现沟内物源总储量约1377.32×104m3,动储量约114.80×104m3,在遇大暴雨时,易形成支沟甚至主沟泥石流。(2)幸福沟为一老泥石流沟,地质历史时期至少发生过5期规模巨大泥石流,各期泥石流堆积体呈扇套扇堆积。根据古泥石流的发育特征,推测其古泥石流活动经历了从活跃到间歇5次循环,而活跃期内又暴发多次泥石流。古泥石流堆积物以岩浆岩为主,据此,推测其物源来源于主沟道左岸的岩浆岩分布区,为茂汶断裂发生的5次大震级古地震产生。(3)幸福沟现代泥石流规模相对古泥石流较小,其发育特征与古泥石流具有一定的相似性。“5.12”地震前,泥石流不活跃,仅在1964年6月及1992年7月暴发过两次泥石流;震后,泥石流进入活跃期,先后于2008年6月和2013年7月暴发过两次规模较大的泥石流,由震前低频泥石流转变为高频泥石流,规模也增大。震后,主沟泥石流为稀性泥石流,主要在沟内相对宽缓处及沟道口堆积,但由于主沟沟道口堆积范围较小,其堆积扇不发育;支沟泥石流多偏粘性泥石流,主要在各支沟沟口堆积,部分进入主沟内堆积。(4)用计算流体力学软件CFX对幸福沟中下游沟段及三条较大支沟下游沟段进行了数值模拟,模拟得到了“7.10”泥石流的速度场、对沟床的剪应力场及压应力场,与采用泥痕调查法计算的“7.10”泥石流速度吻合度较高。因而,P=1%暴雨频率下泥石流的模拟结果,能够为泥石流防治工程设计提供一定参考。(5)在幸福沟古泥石流历史演化成因及现代泥石流发育特征基础上,结合定量计算,推测,震后幸福沟泥石流激发雨量下降了约2/3,未来10年其泥石流活动仍然活跃,支沟较主沟更易暴发泥石流。在前期降雨量充足的前提下,当日降雨量达到105mm时,可激发100年一遇泥石流,规模约15.08×104m3。通过定性分析及对经验公式进行修正后的定量计算,可知当幸福沟暴发100年一遇的泥石流时,其造成渔子溪的完全堵断可能性较大。最后,对幸福沟泥石流采取拦挡、排导、生物工程相结合的综合治理措施。
[Abstract]:The happy gully is a typical valley type debris flow gully. After a large number of massive debris flow.5.12 earthquakes in the geological historical period, a large number of landslides have been produced in the gully area. In 2008, two large-scale debris flows occurred in 2013, which may have occurred again in the near future with large-scale debris flow, which seriously threatens the big bear in the ditch. The research and protection center of the cat, the giant panda Wild training farm and the residents of the gully gundun Township, the safety of the S303 provincial road. Therefore, it is of certain practical significance to study the development characteristics of the debris flow in the happy gully, the characteristics of the movement and the trend of development, which is of practical significance to the design of the debris flow prevention and control engineering. On the basis of the survey, the formation conditions of debris flow in the happy gully, the historical evolution of the ancient debris flow and the activity of the debris flow after the earthquake are studied, and the movement of debris flow in the gully under the "7.10" debris flow and the P=1% rainstorm frequency is simulated with CFX software. On this basis, the development trend of debris flow is predicted and the proposal of the debris flow management project is proposed. The following main understanding are as follows: (1) the gully is a debris flow gully with large basin area and branch ditch development. After the "5.1" earthquake, a large number of landslides and slippery sources are added in the ditch. The total reserves in the furrow are about 1377.32 * 104m3, and the dynamic reserves are about 114.80 * 104m3. In the event of heavy rain, it is easy to form a branch ditch even the main ditch debris flow. (2) the happy gully is an old debris flow. In the gully, there were at least 5 huge debris flows in the geological historical period, and the debris flow deposits in each period were fan sets. According to the characteristics of the paleo debris flow, the ancient debris flow activity experienced from active to intermittent 5 cycles. Its source is derived from the magmatic rock distribution area on the left bank of the main channel, which is the 5 magnitude ancient earthquake of the Maowen fault. (3) the scale of modern debris flow in the happy gully is relatively smaller than the ancient debris flow, and its development features are similar to that of the ancient debris flow. Before the "5.12" earthquake, the mud and stone flow was inactive, only in June 1964 and July 1992. After two debris flows, after the earthquake, the debris flow entered the active period, and two large debris flows were outburst in June 2008 and July 2013. The low frequency debris flow before the earthquake was transformed into high frequency debris flow, and the size of the debris flow was also enlarged. After the earthquake, the debris flow in the main ditch was a RRL debris flow, mainly in the relative width and the gully gully in the gully, but the main ditch was caused by the main ditch. The accumulation area of the crossing is small, and the accumulation fan is not developed; the mudflow of the mudflow in the branch ditch is mostly viscous debris flow, which mainly accumulates in the gully and gully of each branch. (4) the numerical simulation of the middle and lower reaches of the happy gully and the lower reaches of the three larger branches is carried out by the computational fluid dynamics software CFX, and the speed of the "7.10" debris flow is simulated. The shear stress field and stress field of the trench bed are in good agreement with the "7.10" debris flow velocity calculated by the mud mark investigation method. Therefore, the simulation results of debris flow under the P=1% rainstorm frequency can provide some reference for the design of debris flow prevention and control engineering. (5) the historical evolution cause of the ancient debris flow and the development of the modern debris flow in the happy gully. On the basis of the quantitative calculation, it is inferred that the rainfall in the happiness gully debris flow after the earthquake is about 2/3, and the debris flow activity is still active in the next 10 years, and the branch gully is more prone to the mud and stone flow than the main ditch. Under the precondition of sufficient rainfall, the debris flow can be excited for 100 years when the rainfall is reached, and the scale is about 15.08 x 104m3.. The analysis of sexual analysis and the revised quantitative calculation of the empirical formula show that when the happy gully erupts 100 years of debris flow, the possibility of completely blocking the Fishing Creek is more likely. Finally, the comprehensive treatment measures of blocking, guiding and bioengineering are taken to the debris flow of the happy gully.
【学位授予单位】：成都理工大学
【学位级别】：硕士
【学位授予年份】：2015
【分类号】：P642.23

【参考文献】