| Due to the development of urban construction and rail transit,the development and utilization of underground space has effectively expanded the capacity of urban space and alleviated the pressure of urban land resources.The entrance and exit of underground space is an indispensable part of underground space.As the only pedestrian passage connecting indoor and outdoor,it takes into account the city image,cultural history and legal norms when designing.However,as an interface for direct climate and energy exchange between underground space and outdoor environment,the physical environment of entrances and exits directly affects human comfort.However,few entrances and exits are designed to consider the problem of wind-heat physical environment,resulting in unsatisfactory wind-heat environment and human comfort.In addition,the current research on the entrance and exit of underground space mostly starts with the use function of underground space,and fails to classify it by spatial morphological characteristics.Therefore,this paper takes climate exchange as the standard,classifies according to the difference of spatial morphological characteristics,studies the entrance and exit forms under different spatial types,improves the wind and heat environment around the entrance and exit,and improves human comfort.First of all,this research uses the method of literature survey to summarize the literature related to urban wind-heat environment and underground public space entrance and exit in detail.Combined with the research basis of the tutor team,the research methods and research objects of this thesis are determined.Using the method of field investigation,thirty underground public space entrances and exits in Xuzhou were visited and investigated,and the types of underground public space entrances and exits were determined and the appropriate entrances and exits were selected.By using the method of field measurement,the physical data of wind and thermal environment were measured at the entrances and exits of six underground public spaces in three groups of open,independent lobby and sinking square in Xuzhou City,and the spatial and temporal distribution characteristics of wind and thermal environment at the entrances and exits of underground public spaces were analyzed.Based on the test data,the reliability of software simulation in summer and winter is verified by numerical simulation.Secondly,the response surface analysis method was used to set up a four-factor four-level experimental group design,and three types of 150 groups of variable experiments were established.The wind thermal environment of 150 groups of models was simulated and analyzed by numerical simulation method and CFD simulation software.The correlation analysis between the quantitative indexes of the spatial form of the entrance and exit and the simulated wind-heat physical data and human comfort was carried out to find the main influencing indexes.Through the correlation and regression analysis of different elements,the influence of the spatial form factor index of the entrance and exit on the wind and thermal environment of the entrance and exit of the underground public space is judged,and the multiple regression equation of the opening shape,the opening length-width ratio,the opening height-width ratio,the opening depth and the number of vents with the physiological equivalent temperature PET is established.Finally,taking temperature,wind speed and physiological equivalent temperature PET as the optimization objectives,relying on the multiple regression equations of the three groups of spatial morphological elements of entrance and exit types and physiological equivalent temperature PET obtained in the research,combined with the evaluation criteria of human wind comfort,the optimal parameter setting range of entrance and exit spatial morphology is obtained,and the design and simulation verification of actual cases are carried out according to the value range.The main conclusions are as follows:(1)Through the investigation of 30 underground public space entrances and exits in Xuzhou,this thesis maps out the basic spatial form and proportion relationship,and summarizes three basic types of underground public space entrances and exits in Xuzhou divided by spatial feature prototype,namely,open underground public space entrances and exits,independent lobby underground public space entrances and exits,and sinking square underground public space entrances and exits.(2)In summer,the air temperature,black ball temperature and physiological equivalent temperature PET values of the outdoor part of the entrance and exit of underground public space are higher than those of the transition part and indoor part of the whole underground public space entrance and exit space,and the relative humidity is lower than the other two parts.In winter,the air temperature,black ball temperature and physiological equivalent temperature PET values of the outdoor part of the entrance and exit of underground public space are lower than those of the transition part and indoor part of the whole underground public space entrance and exit space.However,for the sunken square entrance and exit,the PET value decreases first and then increases,and the lowest PET value is in the transition part.The wind speed of the outdoor part of the entrance and exit in summer and winter varies greatly,and 70 % is higher than that of the transition and indoor parts.In addition,the outdoor physiological equivalent temperatures of the three types of entrances and exits are quite different.(3)The open entrance is most affected by the number of opening edges and the length-width ratio of the opening.The independent hallway entrance and exit is greatly affected by the single factor opening length-width ratio,the number of vents and the number of opening edges in summer,and is greatly affected by the interaction between the number of opening edges and the number of vents.In winter,it is greatly affected by the single factor opening length-width ratio and the opening height-width ratio,and is greatly affected by the interaction between the number of opening edges and the opening height-width ratio.In summer,the entrance and exit of the sunken square are greatly affected by the length-width ratio of the single factor opening,and the interaction between the length-width ratio of the opening and the number of vents.In winter,it is greatly affected by the length-width ratio of the single factor opening and the height-width ratio of the opening.It is greatly affected by the number of opening edges and the length-width ratio of the opening,the length-width ratio of the opening and the number of vents.The relationship model between the spatial form of the entrance and exit of the open,independent hall and sinking square underground public space in summer and winter and the physiological equivalent temperature PET is established.(4)In order to meet the needs of human comfort in the wind and heat environment,it is most appropriate to select the entrance and exit of the sunken square underground public space in the design,followed by the entrance and exit of the independent hall underground public space,and the entrance and exit of the open underground public space is slightly worse than the former two.Taking human comfort as the optimization goal,the shape of the open entrance and exit should be controlled at 4-5 sides,the length-width ratio should be as large as possible,and the maximum is 3.The depth of the opening should be controlled between 2.2-5.1m according to the depth of the underground space,and the height of the baffle can be set between 0-3m according to whether the iconic sign is needed.The shape of the entrance and exit of the independent lobby type should be controlled between 5-7sides,the aspect ratio of the opening is 3,the aspect ratio of the opening is about0.7-0.75,and the vent is 6;the length-width ratio of the entrance and exit of the sunken square type should be between 1 and 3.1,the height-width ratio between 0.8and 1.2,and the number of vents is 3.This study provides a selection method,design and transformation basis for the design of underground public space entrances and exits adapted to the climate in Xuzhou and Jiangsu cold regions.In order to create a healthy and comfortable wind and heat environment at the entrance and exit,improve human comfort. |
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