Study on Urban Morphology Optimization Based on the Construction of Urban Memory Structure —— Take Dazhi Street in Harbin as an example

In the late 1970s, China began the process of rapid urbanization. With the continuous expansion of urban scale and the rapid increase of urban population, the trend of urban homogeneity is deepening. Some problems, such as the lack of urban characteristics and the destruction of urban memory, are becoming more and more prominent. On the one hand, in the context of globalization, China's urbanization will inevitably be affected by globalization. Globalization not only brings opportunities for the development of cities, but also impacts on the local and unique characteristics of urban culture. Urban cultural connotation is gradually weakening and urban characteristics are gradually disappearing. On the other hand, because of the rapid process of urbanization within a short period of time, urban construction focuses excessively on speed and efficiency, while neglects the importance of urban culture and local characteristics. For this reason, urban construction also lacks the cultural deposits. In addition, in 2001, UNESCO issued the "World Cultural Diversity Declaration", which believes that "cultural diversity is very necessary for human beings, just as biodiversity is to nature."Under the background of globalization, the rapid development of information technology promotes the "global flow" of culture. While enjoying the various conveniences brought by globalization, we need to "stick to the historical foundation, protect local characteristics" and construct a city culture with local characteristics (Nyseth, 2013). Therefore, in order to make up for the lack of urban characteristics in rapid urbanization, the establishment of urban memory structure and the strategy of urban morphology optimization have become the current issues that should be concerned and discussed. Based on this, this paper takes Dazhi Street in Harbin as the research object, combs the historical evolution and development context of Dazhi Street by reading relevant historical documents and collating and comparing several versions of urban planning drawings in Harbin.The combination of questionnaire survey and field research is used to study the architecture, street interface, public space and overall spatial form of Dazhi Street in Harbin. Dazhi Street is a main street of a city which emerged with the construction of Middle East Railway. It has witnessed the development history of Harbin for more than one hundred years, and has rich cultural characteristics and great historical value. Therefore, through the study of Dazhi Street, firstly, we construct a relatively complete urban memory structure. Based on the urban memory structure and the current development situation, we put forward five aspects of urban morphology optimization strategy: the continuation and display of historical context characteristics, the unity and symbiosis of architectural style along the street, the coordination and improvement of urban street functions, the optimization and promotion of urban Street landscape, and the improvement and integration of urban street facilities to further highlight Harbin's urban characteristics. It also provides some reference for other cities with rich historical heritage and prominent cultural characteristics to construct urban memory structure and further enhance their locality and uniqueness.