Research And Optimization Of The Protection Effect Of The Eroded Coastline Rehabilitation On Chu Island

Chu Island is located in Rongcheng City,Shandong Province.It was discovered through field observation that the coastal erosion was extremely serious,and there was an urgent need to establish a protection project to protect the coastline.However,"hard engineering" will disrupt the dynamic balance of the coast and may cause further aggravation of coastal erosion."Soft engineering" is expensive and requires long-term investment.Integrating the advantages of "soft and hard engineering",in 2018,a new type of shoreline protection idea with sandbags as the main body was proposed,and the eroded shoreline of Chudao Island was repaired,and the first domestic on-site erosion shoreline restoration experimental base was established.The ecological bank protection is divided into three sections.Test section-A is a multi-layer sandbag structure;test section-B is a single-layer sandbag + geogrid structure;test section-C is a double-layer sandbag structure.At present,a comprehensive evaluation of shoreline restoration and protection projects has not been carried out.Therefore,this article intends to evaluate the effectiveness of restoration projects from multiple aspects and provide scientific value for coastal beach protection research and engineering design.This article comprehensively evaluates the protective effect of Experimental engineering through four aspects:(1)Field observation and analysis of the stability of the three test sections of the Experimental engineering under extreme environments such as storm surges(2)Measurement of the foot elevation of the revetment to study the impact of wave climbing and coastal protection structures on beach erosion Important role;(3)Through the ultimate strength tensile test of materials,explore the strength attenuation of on-site materials under environmental impact;(4)Set up a fixed observation profile to analyze the evolution of the beach in the study area,and compare the effects of various types of protection schemes on the evolution of the beach.influences.The main conclusions are as follows:(1)Under the action of the large waves caused by the typhoon,the bottom sandbags appeared "pull-out phenomenon" in the multi-layer sandbag test section and the overall instability collapsed,causing the overall instability and collapse;the sandbags in the lower layer of the double-layer sandbag test section Under the impact of the gravel carried by the waves,the test section was severely worn out,which caused the test section to fail;the middle section with the geogrid ran well within two years without any problems,and its protective effect was the best;(2)by sandbags on site According to the sampling analysis,it is found that after two years,the ultimate tensile strength of the geotextile on site has attenuated by about 50%,and the ultraviolet rays have a significant impact on the aging of the bag;(3)through the vertical wall section on the beach and the riprap revetment section,Comparison of unprotected shore beaches found that the protective structure can effectively prevent the shoreline from retreating,and has no obvious impact on the evolution of the beach in front of the shore,achieving the unification of ecology and protection effects.As two of the three test sections of the shoreline repair project completed in October 2018 were damaged during the two years of completion,the project team optimized and repaired this section of the protection project based on experimental data in October 2020.The optimization scheme is as follows: All the shore sections are equipped with geogrids to improve the stability of the revetment and the ability to resist large waves;select acrylic woven bags and needle-punched non-woven bags that are more suitable for the research area environment to replace the previous woven bags;add reinforced microphone pads on the outside of the sandbags To resist the impact of gravel and the aging of sandbags caused by the ultraviolet rays of the shading cloth;reduce the size of the sandbag to facilitate construction.