| In order to share the pressure of heavy traffic and meet the requirements of people's daily transportation,the construction of underground rail transit is becoming more and more general.The construction of metro station involves deep foundation pit engineering,and metro stations are often located in the central area where includes large population,heavy traffic and intensive buildings.In addition,the construction of station will cause soil disturbance,which may lead to the settlement of ground and buildings nearby.The influence factors of ground settlement caused by construction of underground space in large cities are numerous and complicated which becoming one of the key technical difficulties in metro construction,so it is necessary to carry out exploratory research based on new theories and methods.According to its irregular shape,the foundation pit can be divided into square,trapezoid and narrow.This paper studies the correlation between ground settlement and distance from the edge of the foundation pit(use ‘d' for short),and excavation depth.At the same time,the results in this paper are compared with traditional methods.This paper studies the correlation mechanism of same-source common-struct data and different-source common-struct data which is based on Maximal Information Theory,also compares the different correlation mechanism between two types of data above,main conclusions can be drawn as follows:(1)For a foundation pit of which plane form is irregular and narrow,it is necessary to be divided into different shapes to study correlation mechanism of ground settlement.The enclosure structure of the square foundation pit and the reinforced pile can restrain the ground settlement besides the foundation pit obviously,and the restraint effect of the enclosure structure in trapezoidal foundation pit is slightly weaker,which affects the correlation mechanism of ground settlement.(2)The ground settlement doesn't show a single linear relationship with the increase of d and excavation depth.When d ranges from 0~13m,the maximum ground settlement besides square foundation pit increases along with the increase of d,while the maximum ground settlement besides trapezoidal foundation pit decreases along with the increase of d.When d is more than 13 m,the correlation between ground settlement and d is low.With the increase of excavation depth,the distribution of ground settlement is diverse.(3)The correlation of ground settlement along the standard section of the foundation pit decreases with distance increasing,and the influence of distance on the correlation is indistinctive when the distance exceeds 6 times the excavation depth.According to the scatter diagram of the correlation changing with distance,the maximum value of Maximum Information Coefficient decreases with the increase of the distance between the whole measuring points,despiting of the results of a few measuring points which are disperse.However,the maximum value of Maximum Information Coefficient decreases gently when the distance is more than 6 times the excavation depth.(4)For this paper,the correlation between buildings' settlement is stronger than that between building settlement and ground settlement based on the analyses about the settlement of building and ground.That is to say,the correlation between same-source common-struct data is stronger than that between different-source common-struct data.(5)The correlation between monitoring data during the foundation pit excavation is stronger than that during the main structure construction by analyzing same-source common-struct data and different-source common-struct data,and thinking about the plane form of foundation pit.As the excavation of foundation pit has a greater influence on the disturbance of soil,both ground settlement and building settlement will be affected.Whereas,the deformation of foundation pit tends to be stable during the construction of main structure,so the process of construction has less impact on surrounding environment,for which leads to a lower correlation. |
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