Combined support-excavated geologically solutional deep foundation pit and construction method thereof

Abstract

The invention discloses a combined support-excavated geologically solutional deep foundation pit and a construction method thereof. The deep foundation pit is characterized by consisting of an upper slope foundation pit and a lower vertical foundation pit; the construction method thereof comprises the steps that: in case of vertical excavation of the deep foundation pit, the periphery of the foundation pit is supported and reinforced by reinforced concrete support piles to prevent the foundation pit from collapse owing to lateral pressure of soil mass; then a high pressure jet grouting pile waterproof curtain is adopted for performing water sealing on soil mass outside the support piles and a bedrock internal grouting curtain is adopted for performing water sealing on geological situations in rocks, such as solution cavity, solution, crack and the like; and in the process of layered excavation, an annular continuous concrete slab wall is adopted for the soil mass and the rocks at the periphery of the foundation pit to form a continuous arch ring lagging. The construction method according to the invention can effectively guarantee the safe, stable, fast and effective excavation of the geologically solutional deep foundation pit.

Description

technical field [0001] The invention relates to a foundation pit in engineering construction and a construction method thereof, in particular to a deep foundation pit in dissolution geology and a construction method thereof. Background technique [0002] In large-scale construction and road and bridge projects, deep foundation pits are the key to ensuring the anchorage construction, and have a great impact on the subsequent construction of catwalks and main cables of the main bridge. The geological conditions in Southwest my country are complex, and most areas are erosive karst landforms, which brings great difficulties to the excavation of deep foundation pits for large-scale buildings, roads and bridges and other projects. [0003] In engineering, a foundation pit with an excavation depth of more than 5 meters is called a deep foundation pit. In the prior art, for deep foundation pits, the slope excavation in the unsupported state is usually adopted, and the support is co...

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Problems solved by technology

However, under eroded geological conditions, including those with karst caves or fissures, since the excavation depth is often far lower than the normal construction water level, the holes or fissures in eroded geology can easily become channels for groundwater, resulting in water inrush during excavation. Therefore, the slope excavation in the non-support state in the prior art is difficult to guarantee the normal construction. Once the foundation pit support, water stop and other works do not meet the requirements and the foundation pit is affected by the water level or flood, subsequent construction Excavation construction will not be possible

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