Wikipedia explains three archaeological studies of the Jericho site, and concludes that the city was abandoned at the time the supposed Biblical battle took place.
How do Christians reconcile the Biblical account with this science?
The most common response of conservative Christians is to attempt to refute the evidence of archaeology. 1 Kings 6:1 places the Exodus from Egypt approximately 1440 BCE, because this verse dates the Exodus 480 years before the fourth year of Solomon's reign, and the Bible dates this year of Solomon's reign at 960 BCE. This would place the Battle of Jericho around 1400 BCE, long after archaeologists say that the city had been abandoned. The archaeological evidence for the destruction of the walls has been suggested as so imprecise as to make a date around 1400 BCE possible, although this argument is no longer sustainable following carbon dating and other dating methods that confirm Kathleen Kenyon's initial estimate.
Some conservative Christians suggest that the Battle took place earlier than the biblical record suggests, placing it at the time of the actual destruction of Jericho's walls. A problem with this comes from the Amarna letters, which demonstrate conclusively that the Canaanite cities were still ruled by petty kings under the suzerainty of their Egyptian overlords until at least 1350 BCE, with no suggestion of a threat from outsiders. Therefore it is no longer possible to date a military conquest of Canaan until long after 1350 BCE.
Wikipedia states that almost all scholars agree that the book of Joshua holds little of historical value, and so many liberal Christians accept that the biblical Battle of Jericho is not literal history. On this view, historical errors in the biblical account do not alter the underlying message of the Bible. For example, The Catholic Bible, edited by Jean Marie Hiesberger, says (page rg97) "Archaeological excavation supports the conclusion that the stories of conquest found in Joshua were not based on memories of actual battles that took place at Jericho."
What is there to 'reconcile'?
If God's word is true (a presuppositional point I take because God cannot lie and scripture comes from God and the 'battle' record itself starts with "The LORD said to Joshua"), then the science will conform to the Bible, and not the other way around.
As to precise dates - we have several plausible timelines. Starting from the creation of the world, I charted [almost] all of the Bible's characters and lives (that we have years on) through Jacob. Based on a whole-years reckoning of lives, Jacob died ~2255AA (After Adam). Based on several other people's work, I agree that the earth was created in about 4004 BC.
That places Jacob's death (in Egypt) at approximately 1749 BC. From a chronological study of Exodus through Joshua I am currently engaged in, but have not published yet, from Moses' birth to the destruction of Jericho is ~121 years (he dies at age 120, and Jericho is conquered within the next several weeks).
That puts the conquest of Jericho approximately between 1534 and 1219 BC - right in the range as shown in the wikipedia article cited for when Jericho was abandoned.
As a sidebar, wouldn't a city appear to be "abandoned" if it had just been completely destroyed?