Study On Effect Of Green Deep Foundation Pit On Adjacent Building In Swelling Strata

At present, the temporary support is adopted by many foundation pit. The resource can not be used in circulation. With the promotion and implementation of green building and green construction policy, the innovation and breakthrough in the foundation pit supporting engineering is called the subject of every rock and soil engineer.Understand the mechanical properties of expansive soil, calculation basis is provided for the design of the expansive soil foundation pit supporting and finite element analysis method for displacement control. The relationship between water content and cohesion of expansive soil, and water content and internal friction angle was established by the fast shear test of expansive soil with different water content. By the fitting curve of water content of expansive soil and cohesive force and internal friction angle, the internal friction angle and cohesive force decrease with the increase of water cut, and the rate of internal friction and cohesion is slower and slower, finally tends to be a straight line. The water content, cohesive force and internal friction angle of expansive soil can be seen in a 3-D graph, which can be directly seen in the relationship between the three variables. In a three-dimensional space, the shape of the curved surface is presented in the middle and down, and the cohesive force increases with the increase of the internal friction angle.The foundation pit of Huainan Digital Plaza, in the expansive soil, the overall area is 15000 square meters, and the local depth reach to 17 meters. It is close to the traffic trunk road and old buildings, and has high deformation control requirements. Due to these characteristics, the anchoring idea of light pile heavy anchor is put forward. The deformation of foundation pit is controlled by enhancing the anchoring force. Combined support of H steel piles with the single shaft rotary spray mixing inclined pile anchor used for muddy soil. For the first time, this support is used for the expansive soil foundation pit, and good support effect achieved, and shorten the time limit and save the cost effectively. It is proved that the combined support of the rotary jet mixing stiffening pile and the pile is an ideal support for the foundation pit.Based on the completion of the foundation pit, the H type steel can be recovered, and the single shaft rotary spray mixing inclined pile anchor is permanently left in the ground, which the comprehensive maintenance cost of the foundation pit rises. So stainless steel gasbag gas anchor is proposed. The anchor is inflated to the soil near the plastic state, which makes the soil pressure acting on the surface of anchor is increased nearly 4 times. Thus the anti-pull force increased by nearly 4 times. The inflatable anchor can load at once, and the anchor solid is released immediately when is deflated. So the foundation pit green supporting is realized.Deep foundation pit are visually located in the downtown area. Around the foundation pit often have dense buildings, various pipelines, dense metro station, subway tunnels crisscross, showing a deep and large, difficult characteristics. The construction accidents caused by the excavation of foundation pit are frequent, causing heavy casualties and economic losses, which has caused extensive concern of engineering and social.Based on in-situ measurement data of the deep foundation pit engineering in Huainan Road Digital Plaza and correlation theory, the ground surface settlement formula of Ou and Heish is locality revised. The surface deformation due to foundation pit excavation of expansive soil layer are analyzed theoretically. And the three-dimensional settlement prediction curve formula of surface outside foundation pit is is presented.Using the support vector machine (SVM) calculation model based on fish algorithm, the foundation pit excavation of expansive soil layer influence on adjacent buildings is studied. The displacement settlement of buildings and roads adjacent to foundation pit are measured. Selected horizontal displacement monitoring data of adjacent road for machine learning and regression. And on this basis, a prediction is made.Python parametric modeling based on finite element software ABAQUS. By using the displacement control finite element analysis method and combining with the building’s own bearing capacity, the foundation pit deformation control standard of the surrounding existing strip foundation masonry building bearing capacity is proposed. Obtained the relationship between the foundation pit excavation depth and the maximum deformation under the condition of ensuring the construction safety.